SRB History / taxonomy

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Richard F. Hoyer
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SRB History / taxonomy

Post by Richard F. Hoyer » July 22nd, 2015, 5:46 pm

Recently, an individual sent me two boas he found on the S. Kern Plateau. After recording information, the boas were returned per his request and I reimbursed his costs for shipping.

In one of his messages, he mentioned the following: “I am under the impression that the S. Kern Plateau population of boas may be intergrades between the northern and southern types, but more research is needed to verify this. Is there something more that I'm not aware of??.”

Later he wrote the following: “I have a few thoughts/questions for you: - do you think that Charina should just be one species with two subspecies? Or merely one species which tends to be smaller in the southern portion of its range?” “- do you think Charina should be protected from recreational collection anywhere in its range?”

Instead of brief answers, in a series of messages, I provided an overview of the history of the Rubber Boa in southern Calif. with my personal take on the status of the species from what evidence has become available.

In this thread, I will copy the series of messages for a couple of reasons.
1) I am 81 and there is no certainty that the information I have acquired on Charina bottae will ever get into print before I am gone or incapacitated. By producing this overview on the forum, even though a great deal of what I mention is of an anecdotal nature and thus not valid from a scientific perspective, it nevertheless can provide some measure of understanding and insight along with how I view / interpret the existing evidence.

2) And a second reason for posting this overview is to urge others that venture up to the Kern Plateau to keep me in mind. My sample size is now 21 specimen from that region of the extreme southern Sierras. Additional specimens are needed towards achieving a more representative sample that could then be treated in a professional manner.

Last, my skills with the written language are not one of my stronger points. And secondly, much of what I relate in this series of messages has been from memory although I did look up some of the details.

Best to everyone. Richard F. Hoyer (Corvallis, Oregon)
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Episode #1: I will recap some history then later, relate more recent developments and add my personal perspectives. Keep in mind that ‘perspectives’ can change with the revelation of new information.

In 1943, Lawrence Klauber proposed the subspecies Charina bottae umbratica or the Southern Rubber Boa, based on his examination of two preserved specimens, one each from the San Jacinto Mts. and San Bernardino Mts. Klauber also resurrected the Great Basin subspecies, C. b. utahensis, that has been discounted by previous authority.

In 1964, UCLA Dr. John Cunningham published a note on the SRB where he had recorded scalation data on a number of specimens from the San Bernardino Mts. Cunningham’s report supported Klauber’s subspecies arrangement.

I believe either in 1970 or early 1971, the CDFG (now CDFW) convened a panel of herpetologists (and perhaps others such as wildlife biologists), to assess the status of various herp species of possible conservation concern. One of those individuals was Dr. Glenn Stewart of Cal. Poly Pomona. I believe Glenn mentioned that Dr. Robert Stebbins was another participant.

I wasn’t there so do not know what actually transpired. But from the input I once received from Glenn, the consensus of those individuals indicated the SRB to be of conservation concern as 1), it was infrequently encountered and 2), there were few voucher specimens in the various collections.

Neither of those factors are a valid means for assessing species. There are a number of explanations that can account for those two factors other than a species is numerically rare. Historically as you may know, many amateur and professional herpetologists, wildlife biologists ,and others have considered the Rubber Boa as being rare over its entire distribution. As a freshman at OSU in Wildlife Science, I was told that very thing by one of my professors who was a herpetologist.

At any rate, based on the perceptions of those panel members, in 1971 the CDFG declared the SRB to be “RARE” and thus protected. Sometime in the early 1980’s I believe, the agency change the designation to ‘Threatened’ to conform with federal designations.

In his 1943 paper, Klauber mentioned a boa had been found on Mt. Pinos in the mid 1930’s, taken to UCLA but escaped before it could be examined. So the species was assumed to occur on Mt. Pinos but to which subspecies that population belonged was not known. In 1973, Glenn Stewart found one live and one DOR boa on Mt. Pinos thus confirming the species occurs there. The same year, Glenn confirmed the species occurred in the Tehachapi Mts.

In 1974, I published my first paper on the boas from Oregon and noted that the subspecies arrangement of C. b. utahensis and C. b. bottae did not work in Oregon. That same year, Dr. Ron Nussbaum and myself published a paper that reported on the species throughout it range in the northwest. That paper also dismissed the Great Basin subspecies as not being valid due to the large amount of overlap in defining scalation features. But Ron went a step further and dismissed the SRB as a valid subspecies based on what he mentioned as a non-concordance of keycharacters and clinal variation.

Since I had not examined any SRB specimens, at the time and thereafter, I always felt a bit uneasy about that
particular part of our paper. From that point on, the Great Basin subspecies was dropped but the SRB continued to be accepted as being a valid subspecies along with the N. Rubber Boa, C.. b. bottae.

In the late 1970’s and early 1980’s, Glenn had some of his grad students conduct surveys for the boa mainly on Mt. Pinos and the San Bernardino Mts. but they did some searches in the San Jacinto Mts., and a couple of other mountain near Mt. Pinos. Those efforts primarily were meant to assess the distribution of the SRB in the San Bernardino Mts. and potentially determine the relationship of the boa populations on Mt. Pinos and the Tehachapi Mts. The samples Glenn obtained from the latter two regions did not allow him to make any definitive statement as to the relationship between those two populations and the SRB populations.

Richard FH
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Episode #2:
Despite there being many professional herpetologists in the greater metropolitan area of southern California, no one ever attempted to undertake a life history study of the Rubber Boa or S. Rubber Boa. Except for a number of published scientific notes or shorter communications that mentioned aspects of the species’ life history, most all other published accounts dealing the C. bottae pertained to taxonomy.

I suspect that the reason for the lack of ‘interest’ was due to the fact that it was general knowledge the species was rare and thus trying to acquire a decent sample on which to base research was considered to be too difficult. In 1962
I had success in maintaining two boas and by 1965, the male had reached mature status and was noted courting the adult female. It was then that as a serious hobby, I made the decision to pursue research on the species. I went to the OSU library and found that little had been published on the boa. In a week or less, I became acquainted with all that had been written on the species.

In the early 1970’s. I became acquainted with Dr. Glenn Stewart due to our mutual interest in the Rubber Boa. In 1973, Glenn sent me information he had recorded on I believe all preserves Southern Rubber Boas, about 19 in all. In reviewing that information, I noted that the lengths ranged from about 11 inches to 19 3/4 inches. A random sample of Oregon boas surely would have included specimens in the neighborhood of 24 inches or greater. In my response to Glenn, I wondered if the SRB was a ‘dwarf’ form of the species.

Fast forward to late 1991. I retired at the end of Oct. 1991 and in early 1992, I contacted Glenn Stewart and proposed we undertake a 4 – 5 year field / laboratory study of the SRB in the San Bernardino Mts. Glenn accepted my proposal and thus in mid May, 1993, I came down to the San Bernardino Mts. and began that study that lasted until the early fall of 1997. During those years, I would come down for from about 10 days to 3 weeks and make searches then come back down the following Sept. or Oct. to release any SRBs I had taken to Oregon.

Our results were published in two paper in 2000. When I initiated that study, I had four goals. The first was to try and record as much life history information as possible on the SRB. Then, determine if the SRB was truly rare as I had my doubts. Third, determine if the SRB was indeed a dwarf form of the species. And last, record information that pertained to taxonomic issues.

During my 10 day stay in mid May, 1993, I found no SRBs as it was too hot and dry. In 1994, I arrived in mid April and spent 3 weeks making searches and setting up sites with artificial cover objects. During that time, I found a single SRB. Each of those summers after returning to Oregon, I wrote Glenn that I was still very much enthused about the project as all indicators I had viewed suggested the SRB had to exist in decent densities.

In 1995, I arrived at the US Forest Service Arrowhead Ranger station on a Friday, March 31st. at near 6 PM. The only perk I had during that study was the fact I was allowed to stay in the fire barracks at the ranger station each year. Arriving after closing hours, I thought I was going to spend the next three nights in the back of my pickup. By luck, a receptionist was still in the headquarters building so I could get a key to the fire barracks.

She recognized me and acted extremely surprised to see me. When I inquired why that was the case, she said I had been the laughing stock of the entire forest service personnel as here was this “hot shot boa guy” from Oregon and in two years had come up with but a single SRB. That is why no one expected to see me back in 1995. And that was all the proof they needed to confirm that the SRB was indeed rare.

In about 8 - 10 days at the first of April that year, I captured 26 SRBs. That number equaled or exceeded the number of voucher specimens of the SRB in all collections. Glenn’s MOU (legal document) with the CDFG indicated we could retain up to 20 SRBs per season for up to 180 days. So I retained 18 to take back to Oregon and released the other 8.

Glenn had pretty much adopted the conventional wisdom that the SRB was rare despite the reasons I had proposed in earlier years as to why that likely wasn’t the case. After all, that was the same conventional wisdom that had the species rare throughout its distribution. In Oregon, I had demonstrated that the perception of ‘rarity’ was a myth.

At any rate, through 1997, I was able to record data on a representative sample of 83 initial captures and 21 recaptures, large enough so that the data could be treated statistically by Glenn. And it was large enough to provide solid clues to the first three goals mentioned above. There was new information reported on various aspects of the SRB life history and the life history of the species in general. Secondly, instead of being rare, the SRB was shown to occur in decent densities in comparison to all other species of snakes encountered during the study. In fact, the data suggest that the SRB is more than likely the most abundant species of snake in the San Bernardino Mts. from about 5500 ft. on up. And third, it was confirmed that the SRB was indeed a stunted or dwarf form of the species.

As for the last goal relating to taxonomy, to help resolve that issue, representative samples from boa populations elsewhere in S. Calif. were needed. And that is precisely what I have been trying to accomplish since late 1997.

Richard FH

Richard F. Hoyer
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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 22nd, 2015, 5:52 pm

Episode #3:
During the last year (1997), of the SRB study in the San Bernardino Mts., I began making searches in the Tehachapi Mts. and on Mt. Pinos. By 1999, my sample of captured boas from the Tehachapi Mts. was large enough to come to the realization that population also was of the dwarf form of C. bottae. Obtaining a representative sample from Mt. Pinos took much longer and was finally achieve due to the help of some great herpers on this forum. So as of now, it is clear that those boas are also of the dwarf form as well.

In May, 2000, I began accumulating data on the boa population on Breckenridge Mt. due north of the Tehachapi Mts. and about 35 miles east of Bakersfield. Then in 2001 and 2002, I had begun gathering data on the boa populations in the Greenhorn Mts. due north of Breckenridge Mt., the Piute Mts., due east of Breckenridge Mt., the Scodie Mts. due east of the Piute Mts. and the Southern Kern Plateau north of the Piute and Scodie Mts. and Lake Isabella.

Getting along in age, I made the decision to concentrate what time I had left trying to acquired data on a samples from Breckenridge Mt. and the S. Kern Plateau. So my sample from the southern and northern parts of the Greenhorn Mts. are not large. I decided not to tackle the Piute Mts. so visited there just once and have data from only one or two specimens.

Same thing applies to Alamo Mt., Frazier Mt., Mt. Abel, west of I-5 and the Scodie Mts. which I visited just twice with Brad Alexander. But with great fortune, a week before I arrived at Kernville in 2002, Brad, Robert Hansen (Herp Review Ed.) and others had visited the Scodie Mts. and Brad found a gravid female boa. That female produced five neonates that late summer from which I was able to record pertinent information.

One of the key indicators as to whether a boa population belongs to the dwarf or large phenotype can be made by information obtained from litters. Data was obtained from 12 SRB litters during that study which serves as
baseline information on neonates of the dwarf form. Litters have been obtained from the boa populations in the Tehachapi Mts., Mt. Pinos, the S. Greenhorn Mts., Scodie Mts., Breckenridge Mt., and the S. Kern Plateau.

All of the gravid females that produced litters from those localities were well within the size range of the gravid SRB females. And the range of lengths of all neonates from those localities are comparable to the range of lengths of the SRB neonates. Even without sophisticated analysis, a reasoned conclusion is that the boa populations from Mt.Pinos, the Tehachapi Mts., Breckenridge Mt., Scodie Mts., and the S. Kern Plateau are all of the dwarf phenotype similar to the SRB population in the San Bernardino Mts.

The jury is still out for some of the other populations. This would include 1) the SRB population in the San Jacinto Mts., 2) the boas known to occur on Mt. Abel, Frazier Mt., Alamo Mt., and other associated peaks in the greater Mt. Pinos region, 3) the Piute Mts., and 4) the Greenhorn Mts. But by geographical proximity to known dwarf populations, it is reasonable to assume that the above mentioned populations are also of the dwarf form.

The one exception might be the boas in the southern Greenhorn Mts. which is the southwestern extension of the main Sierra Nevada Mt. range. The boas in northwestern Tulare Co. (Sequoia Nat. Park) are known to be of the large phenotype. With continuous suitable boa habitat from north to south from southern Tulare into northern Kern County in the Greenhorn Mts., there has to be some genetic influence of the large morph from north to south.

I would have thought that would be the case with the boas on the S. Kern Plateau as well but as of now, all data thus far collected strongly point to that population belonging to the dwarf phenotype. However, the sample stands at 21 which is too small for really form solid perspectives.

Richard FH
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Episode #4:
With respect to taxonomic issues, by the late 1990’s, I had captured a sizeable sample of boas from the Tehachapi Mts. and a few from Mt. Pinos. The information I recorded indicated there occurred considerable overlap in scalation features in the boas from those two populations with the SRBs. That is, an unknown but sizeable percentage of boas from the Tehachapi Mts. and Mt. Pinos would key to be Southern Rubber Boas while the majority would key out to be Northern Rubber boas. At the time, I was also aware that in using Klauber’s key, there was a certain percentage of SRBs that would not key out to be SRBs.

The problems, as I later surmised, were two fold. 1) Klauber had established his key based on just 2 SRB specimens. 2) The second disadvantage Klauber faced was a lack of geographical representation. He was aware the species occurred on Mt. Pinos but with no vouchers to examine. And the species had yet to be documented from the Tehachapi Mts., Breckenridge Mt., the Greenhorn Mts., the Piute Mts., the Scodie Mts. and Southern Kern Plateau. At that time, the furthest known southern distribution of the species in the Sierras was in the vicinity of Sequoia National Park. Thus, most comparisons Klauber made were between the 2 SRB specimens and boas from the main Sierra Nevada Mts. and boas of the Bay Area. To this day, such a comparison is striking and thus understandable why despite only having two SRB specimens, Klauber went forward with recommending a third (SRB) subspecies.

Klauber’s 1943 key was suppose to allow a person to distinguish Southern Rubber Boas from boas belonging to the Pacific (Northern) Rubber Boa populations. But mainly due to the above two considerations, his key has turned out to be less than reliable. This is very similar to the situation I discovered in Oregon. Klauber’s key to subspecies was suppose to allow identification between the Pacific and Great Basin subspecies in which the latter occurred east of the crest of the Cascade Mts. and the former occurred west of the Cascade Mt. crest. Here again, it is my view that a lack geographical representation and sample size resulted in a key that has turned out to be unworkable.

What transpired is that 40 % of the boas east of the Cascades in Oregon that were suppose to be the Great Basin subspecies would key out to be the Pacific subspecies. And the reverse also occurred in which 40 % of the boas west of the Cascade crest that should have been the Pacific subspecies would key to the Great Basin subspecies. in this same vein, about two years ago, I wrote Glenn and others that at that time, about 38 % of the Mt. Pinos boas would key out to be SRBs whereas the other 62 % would key out to belong the the NRB subspecies.

So at the present time, because there occurs considerable overlap in the key morphological traits between the SRB and boas from other populations, identification of subspecies based on scalation features is not reliable. Recognizing that problem, either in late 1998 or in 1999, I began to collect tissue samples from many boa populations. In 1999, I searched for an investigator or lab that would undertake a molecular study to try and help resolve the taxonomic relationships between the various boa populations. Someone at OSU gave me the name of Drs. Javier Rodriguez-Robles and Ted Papenfuss at UC. Berkeley. When I got in touch with Javier, I found that he and Ted Papenfuss were already in the preliminary stages of such a study. I then got them in touch with Dr. Glenn Stewart at Cal. Poly, Pomona.

I had offered tissue for the study but Javier only wished to use tissue from specimens that had been vouchered. Since I release all boas for mark / recapture efforts, I believe only one boa I had collected ended up in that study, a male boa from the Tehachapi Mts. that had died and I gave to Dr. Robert Stebbins then living in Kensington.

In 2001, Javier, Stewart, and Papenfuss published their mtDNA study of the Rubber Boa. Their results demonstrated that the SRB was a very distinct genetic unit that exhibited a significant degree of divergence from all other boa populations that Javier tested. Javier placed all boas into two major clades. The southern clade included the two Southern Rubber Boa populations from the San Jacinto and San Bernardino Mts. The northern clade consisting of all other boa populations he had tested or all Northern Rubber Boa populations.

For that paper, Glenn devised a key that was somewhat different from Klauber’s key. The authors thought that with a reasonable degree of certainty, the key would allow an individual to distinguish SRBs from NRBs. Glenn sent me a pre-publication draft of that paper and I voiced a number of reservations including the point I didn’t think his key of morphological traits was workable. At any rate as you now know, based on the mtDNA results and the key the authors thought was workable, Javier suggested elevating the SRB from subspecies to species status.

Richard FH

Richard F. Hoyer
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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 22nd, 2015, 5:55 pm

Episode #5:
Fast forward a few years. I believe that sometime in 2005, Glenn got in touch with me indicating he had a grad student, Richard Toshima, that wished to do an expanded mtDNA study similar to the one Javier had published. This was to be Rick’s master’s thesis project. Rick was Glenn’s last grad student as Glenn was near retirement. Glenn was aware I had saved a considerable amount of boa tissue from many localities and thus wondered if I would donate tissue for that study and I agreed.

Once Rick was ready to receive tissue, I would suggest they test tissue from this or that locality and give my reasons. Glenn would get back to me as to what samples they wished to have me send. Rick was barrowing lab space from another professor at Cal Poly which ended up with his having time limitations for conducting the study. There also was some financial considerations that would limit the number of samples he could test. I believe I began sending tissue sometime in 2006.

On 7/12/07, I sent Glenn and Rick 14 samples of tissue that turned out to be the last samples I sent as Rick had to give up the barrowed lab space. Of those 14 samples, 5 were from the Greenhorn Mts. north of Alta Sierra and 5 were from the Greenhorn Mts. south of Alta Sierra. The last recommendation of tissue I urged that Rick test were samples taken from boas on the S. Kern Plateau. They agreed to run those four samples so the last four tissue samples I sent were from the boa population on the S. Kern Plateau. I later urged they test the samples I had from the Scodie Mts. but it was too late as Rick was about to relinquished his lab space at Cal. Poly or had done so.

Rick’s mtDNA results on those last four tissue samples produced a huge surprise. That is, the boa population on the S. Kern Plateau nests in the southern clade along with the two SRB populations in the San Jacinto and San Bernardino Mts. One would more likely have surmised that the boas on the S. Kern Plateau, which is the southern most extension of the main Sierra Nevada Range, would nest with the northern clade similar to all other nearby boa populations from the Greenhorn Mts, Piute Mts., Breckenridge Mt., Tehachapi Mts. and Mt. Pinos and populations Javier and Rick had tested further north in the main Sierras.

Just like the boa populations on Mt. Pinos, the Tehachapi Mts., and Breckenridge Mt., the boas on the S. Kern Plateau possess overlapping scalation features with the SRBs in that some of those boas key out to be SRBs while others (I estimate half or more), key out to be NRBs. And this is why there is a need to obtain a larger sample of boas from the S. Kern Plateau at it is important to obtain data on a more representative sample.

But up to this point in time and from a morphologically standpoint, the boas from the S. Kern Plateau cannot be considered as another Southern Rubber Boa population. Just like the boas from Mt. Pinos, Breckenridge Mt., and the Tehachapi Mts., morphologically the S. Kern Plateau boas are basically a NRB population but with mtDNA that happens to nest with the southern clade rather than with the northern clade.

I know little about the finer points involved in taxonomy. So once (and if) all details are made available to taxonomists, they will be in a position to try and sort out these ‘irregularities’ and relationships. But from my
personal perspective, Rick’s findings, along with the information on morphological features coupled with the dwarf scenario occurring in boa populations that nest with both northern and southern clades, not only shoots down the separate species scenario, such information also tends to relegate the subspecies arrangement as less than meaningful.

Richard FH

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Episode #6:
As for your question, I never adopted the notion that there were two distinct species in the genus Charina.

During my SRB study from 1993 – 1997, at first I was ready to concede that the SRB could be a subspecies despite my knowledge that the Rubber Boa exhibits a wide range of genetic diversity when it comes to scalation features. As I have mentioned, I can identify all specimens one from another by their individual scalation traits which from all indications, are genetically controlled.

Over the years, I have learned there is a 'geographical component' to certain scalation traits. As examples, the boas from the Wasatch Range in Utah have a high incidence of having two loreals on one or both sides of the head whereas in most boa populations, having more than one loreal is uncommon. The boas from the mid Sierras exhibit a high incidence of having 11 and 12 supralabials. In all other populations I have examined, the usual number is 9 and 10 supralabials where 11 in uncommon and 12 is very rare.

An extreme example is the boa population in the Hyatt Lake region of southwestern Oregon that exhibit an unusually high number of prefrontal plates. The normal number of prefrontals for boa populations is 2 or 3 with 4 or more being uncommon to rare. I would estimate that the mean number of prefrontal in the Hyatt boa population lies between 4 and 5 with a range of 2 – 9. Finding boas with either 2 or 3 prefrontal in that population in far less common than boas with 4 or more prefrontal.

In addition, the Hyatt population exhibits a high incidence of specimens with divided frontal and parietal plates. I have found some other populations with a high incidence of split parietals but not split frontal plates, a condition that is very uncommon in most other boa populations. I venture to say, if Klauber or others had recorded data on the Hyatt Lake boas, they would have suggest subspecies or even species status. If my memory serves be correctly, in the late 1800’s and early 1900’s., a number of individuals had the boa in 2 – 3 different genera and 3 – 4 separate species based on the genetic variation exhibited they observed in various specimens.

Thus, finding one or more traits that seem to be ‘unique’ to this or that geographical population, such as the SRBs in the San Bernardino Mts. or at Hyatt Lake renders such a set of traits as not being all that meaningful.

And when I began finding that the defining traits that were suppose to be unique to the SRB did not hold up, that is, many specimens from other populations would key out to be SRBs, I then questioned the validity of the subspecies designation as well. I have mentioned to Glenn and Rick that perhaps Ron Nussbaum had been correct all along, that the SRB did not deserve subspecies status due to non-concordance of key characters and clinal variation.

That is, there is a cline (decline) in maximum mid dorsal scale counts from the mid Sierras south to the Southern Greenhorn Mts. to Breckenridge Mt., to the Tehachapi Mts., to Mt. Pinos, and then to the San Bernardino Mts. The same might be said for ventral counts as they too seem to decline in number in a southward manner. But at this point, this is just conjecture on my part as I have not analyzed the data from all populations.

If I were to suggest subspecies, at this point I would place all populations that exhibit the dwarf phenotype in to one subspecies and all large morph populations in a second subspecies. From the information I have acquired thus far, all dwarf populations appear to be quite uniform as far as their range and mean lengths. Secondly, the size at which males and females reach mature status appears to be about the same. And third, the range and mean lengths of neonates produced by each dwarf population all appear to be close to the same. Far greater variation in those same traits occurs between populations of the large morph.

I can think of two other factors that lend support to the distinct nature of the dwarf phenotype and that all such populations are likely to be related.
1) As far as what is now known, all known dwarf morph populations are clustered together in S. Calif. on isolated mountain peaks and ranges.

The exceptions to being ‘isolated’ are the boas in the Southern Greenhorn Mts. and on the S. Kern Plateau. There is continuous suitable boa habitat from the southern to northern parts of the Greenhorn Mts. up to where the large morph is known to exist in central to northern Tulare Co. So it is very likely that if indeed, the southern Greenhorn boa population is of the dwarf phenotype, somewhere they have to come in contact with the large morph and thus intergrade. This suggests that large morph genes likely ‘infiltrate’ to the south and dwarf morph genes ‘infiltrate to the north. I have some data in supports that scenario.

As for the Kern Plateau population, perhaps there is some historical / geological explanation (volcanism, faults, ice age, large lake, elevation, weather), for that population seemingly having been isolated from populations of the large morph further north in the Sierras and from other nearby dwarf morph populations that nest with the northern clade.

2) For the most part, the separation in size between large and dwarf morph populations seems to be pronounced and consistent. That is, there is not a great deal of overlap with respect to A) adult male and female lengths, B) lengths at which males and female reach mature status, and C) the range of lengths of neonates.

Now there are two exceptions (of which I am aware) in which there occurs a greater amount of overlap. Large morph populations further north that occur at rather high elevations that have shorter active seasons tend to be smaller than their large morph counterparts at lower elevation. Such higher elevation large morph populations do not grow as large and maturity is reached at shorter lengths than large morph populations at lower elevations. Also, high elevation large morph neonates tend to be smaller in their range and average lengths so that there is a greater amount of overlap between the smallest of such neonates with the largest of the dwarf morph neonates.

And there is a second ‘glitch’ as well. The boa population in the greater Mt. St. Helena region, where Napa, Lake, and Sonoma Counties come together, are an enigma at this point in time . My sample size is too small to reach any firm conclusions. That being said, the maximum lengths attained by that population seems to be much smaller than the usual large morph populations even at high elevation. Yet the largest adult female from that population has attained a greater length than the largest known dwarf females. And secondly, the range and mean lengths of neonates are very similar to the dwarf form of the species. But here again, from one litter from that population, two or three neonates were larger than any neonate I have recorded from the dwarf morph populations.

Richard FH

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Re your question, “- do you think Charina should be protected from recreational collection anywhere in its range?”

No, never, cannot happen. If you wish to inform yourself about the issue of ‘collecting’ and you haven’t done so already, I suggests you go to the ‘board’ forum and review the extended thread that I started entitled ‘Protection – a flawed policy’.

Incidental , random collecting by humans cannot possibly produce negative affect to all but the smallest and most restricted populations of herps. And taking into account that some species like the boa, are mostly secretive / fossorial, such collecting simply cannot pose a problem including the SRB populations in the San Bernardino and San Jacinto Mts.

Richard FH

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Speckled Rosy
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Re: SRB History / taxonomy

Post by Speckled Rosy » July 22nd, 2015, 8:00 pm

Great write up! I have been recently wondering if Rubber Boas have been found on Reyes peak in Ventura co? Any records?

-Dan

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Brian Hubbs
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Re: SRB History / taxonomy

Post by Brian Hubbs » July 22nd, 2015, 9:16 pm

Very nice recounting of events Richard. Now, answer Danny's question about Reyes Peak... :lol:

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Re: SRB History / taxonomy

Post by FunkyRes » July 23rd, 2015, 4:44 am

If I read it right - scale counts are useless because there is too much variety. A locality may be fairly consistent but there is too much variety from locality to locality amongst populations that appear to have continuous gene flow. So in the Rubber Boa complex, scale counts are not a reliable metric.

With respect to size, there are basically two different forms - large form and dwarf form. There are also mtDNA lineages. But the two are not consistent, in that some of the large phenotype have the dwarf form mtDNA lineage.

Perhaps this is a case where speciation is in process but has not finished, or perhaps the dwarf form with the mtDNA more common with the dwarf form is a distinct species and the dwarf forms with the mtDNA of the larger form are part of the larger form species but dwarf either from convergent evolution, borrowed genes (introgression), or are still same species as the larger form because they continued to receive gene flow while the rest of the smaller form became isolated.

Maybe the easiest thing to do is just call them all Rubber Boas and specify the population morph and general locality.

My understanding is the Cascades Frog is similarly confusing, especially when the DNA is looked at, and they are all just called Cascades Frogs.

I think sometimes our need to classify populations into species and subspecies doesn't always fit nicely with what nature is doing.

Richard F. Hoyer
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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 23rd, 2015, 8:08 am

Dan;
Quite a few years ago, I recorded information on preserved boas from all of the major institutions in Calif. and the Smithsonian. I am certain there were no boas from Reyes Peak at that time. I am not aware of any report of the species from Reyes Peak since that time.

I ‘Googled’ Reyes Peak and from the elevation (7514 ft.) and some of the photos of habitat on that peak, it would seem both factors would be suitable for the species.

But one would have expected by that if the species did occur on Reyes Peak, it would have been reported by now. That being said, I know better than to discount that possibility. It was just a couple of years ago that the species finally was documented to occur at the state park in San Luis Obispo County.

There also is a peak with decent elevation west of Mt. Pinos and Mt Abel that I thought might have the species. But Dr. Sam Sweet of U.C. Santa Barbara once told me he had not observed the species on that peak. (I don’t recall the name of the peak.). And Sam would likely be the person to provide some input with respect to Reyes Peak as well.

Richard FH

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 23rd, 2015, 1:46 pm

FunkyRes;
I would not go so far as to say various scalation features are useless when comparing populations. But the two keys that Lawrence Klauber and Glenn Stewart devised using scalation features to identify subspecies are what I now consider as having questionable value.

Maximum, mid-dorsal scale row count is one of three the factors that were used for being able to distinguish subspecies. From my recording data on a number of Rubber Boa populations in S. Calif., there is far too much overlap in the range of maximum mid dorsal scale counts between those populations.

I took some time this morning to very quickly review some of that data on maximum, mid dorsal counts as follows #;
N Range means
San Bernardino Mts. (SRBs) 74 36 – 42 39.69
Mt. Pinos 53 39 – 45 42.01
Tehachapi Mts. 65 39 – 45 41.83
Breckenridge Mt. 76 40 – 47 43.51
S. Greenhorn Mts. * 12 40 – 45 42.92
N. Greenhorn Mts.** 16 43 – 47 44.93
S. Kern Plateau *** 21 38 – 44 41.30

# Counts taken form live samples (Have data on preserves samples from some regions as well.)
*south of Alta Sierra ** north of Alta Sierra
*** one specimen with 38, next lowest is 40. (Not included is a neonate from one litter with 45.)

If the raw data were to be treated statistically, such treatment might find differences between populations to be significant at some level of confidence.

But another way to view the data would be to chart the number of specimens in which overlap occurs between the SRB and other populations. By doing so, I believe it would become evident that the use of maximum, mid-dorsal scale row counts becomes unworkable when trying to identify many individual boas as to subspecies.

As for speculation about molecular and nuclear DNA, that is mostly beyond my grasp. However, I have made some controlled crosses between dwarf and large morph phenotypes that has also produced some puzzling results.

Richard F. Hoyer (Corvallis, Oregon)

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Re: SRB History / taxonomy

Post by Brian Hubbs » July 23rd, 2015, 7:47 pm

Could it be that the dwarf boas are the same as the northern boas, but just a clinal variation as the species reaches it's southern limits? There are places within the Cal King range where the snakes do not reach the same lengths as most populations, being 30-36 inches on average, as opposed to 40-48 inches elsewhere, but they are the same species and subspecies. I find it interesting that some people want to micro-manage one species based on size, but completely ignore the same trait in another species.

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Re: SRB History / taxonomy

Post by FunkyRes » July 23rd, 2015, 10:08 pm

How communal are Rubber Boas?

I have only ever had two specimens, both of which I kept, when I was in my teens.

I had a male I collected in West Contra County near Richmond, CA - possibly within the city limits, I don't know, and a younger female I collected in the hills of El Cerrito.

Neither were adults when collected.

The male I collected first, and he did not eat. Until that same year I found and collected the female. I kept her in the same enclosure, and once she was in the enclosure with him, he ate the very next feeding attempt and was never a problem feeder after that.

It could be coincidence, it could be he preferred lizards and all I offered him was fuzzies and he finally just got hungry enough. However I doubt that because when I showed him to Stebbins (his wife attended same church, and he often did, though he walked out on sermons more than once when the pastor said offensive things about evolution being bogus or once when the pastor said donating to save the whales was a waste money and we should donate to the church) - Stebbins showed me scars on his tail that were likely from momma mouse attacking the tail as he ate the young.

I never bred them, but the two together, he always ate. I have wondered since then if there is a communal aspect to them and they like to be in the presence of other boas, at least some of the time.

I gave them away to someone I met at East Bay Vivarium who really wanted them, and I had to downsize my collection of herps (spending summer away from home, mom loved snakes but didn't want to be responsible for how many I had), and I regretted it almost instantly.

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 24th, 2015, 8:01 am

FR;
Adult male Rubber Boas emerge from brumation first to thermoregulate. By March, it is very common to find two or more adult males together thermoregulation under the same cover object. This year, I recall finding eight adult males under a piece of tin that was about 18 inches square.

The second situation in which aggregations of boas sometimes occur is during the mating season. In the early 1970’s on an Easter day along S. Commercial Ave. in south Salem, Oregon, I stopped to turn a large sign laying in a vacant lot. Under that sign were two adult females in reproductive condition along with 7 adult males.

And speaking of the East Bay Area, in the 1970’s a boy in high school living in Richmond wrote to me and thereafter, we exchanged a number of letters. His name was Alexander K. Johnson and I believe his father was a professor at U.C. Berkeley. Alexander found a fair number of boas in the hills east of Richmond up near San Pablo reservoir as I recall.

For a year or so, he attended Humboldt State but then ‘disappeared’. There are a number of vouchers of various species he donated I believe, at both the Mus. Vert. Zoology at U.C. Berkeley and at Humboldt State.

I have seen a grand total of just three live Rubber Boas from the East Bay area. I grew up in Oakland and when in the Boy Scouts, our scout master took us to Tilden Regional Park and there he showed us a juvenile Rubber Boa someone else has found.

Then a good number of years ago, William Flaxington (Fieldnotes) took me to the hills above Tilden where he had found an adult female boa. At the time, an adult male boa from the Oakland / Berkeley hills was being maintained by Mitch Mulks at U.C. Santa Cruz. Later, Mitch donated that male to me. I produced either 2 or 3 litters from that pair on which I was able to record information. I eventually transferred both adult boas to my son.

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Re: SRB History / taxonomy

Post by Fieldnotes » July 24th, 2015, 5:00 pm

I printed out the papers to read over time, but once i got started couldn't put it down; very interesting, so much so that it stirred a few ideas/questions.

Many animals are known to become larger when they eat more and this is especially true with reptiles. Some have said a snake will never stop growing so long as it keeps eating. With that in mind, has it been proven that the San Bernardino population is even dwarfed, or is the growth rate related to its environment. In your article you mentioned animals at high elevations having stunted growth, thus one should expect boas dealing with cold and drought will also be stunted due to their limited feeding opportunities.

In the Sierra Nevada, it is possible to find salamanders active in July and by converging to one of the abundant streams, activity can continue well into September. On the other hand, water is not as readily available in the San Bernarindo Mountians and in the rain shadow of the Greenhorn Mountains the Kern Plateau is too dry.

Has anyone attempted to take several neonate Northern Rubber Boas and neonate Southern Rubber Boas and simultaneously rear them on the same diet and environmental conditions (temperature, etc.) to see if they achieve conflicting lengths as adults?

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Re: SRB History / taxonomy

Post by Speckled Rosy » July 25th, 2015, 7:30 am

Thanks for the informative reply Mr. Hoyer.. I think I know the mountain to the west of Abla, you are refering to.. The San Rafael mts, big pine peak? That would also put the SRB in Santa Barbara co. I think its possible, especially Reyes peak. I'll have to try up there the next chance I get..

-Dan

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Re: SRB History / taxonomy

Post by Joseph S. » July 25th, 2015, 11:05 am

I wonder how many herps are truly rare across a large area. Localized I couldunderstand...

The life history of small snakes suggests to me it would simply not work for a species to occur at very low densities.

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 25th, 2015, 12:13 pm

William;
Below is my take. Others more knowledgeable (Dr. Sweet), perhaps can chime in with better insight.

Observations alone tell us that size and growth in all organisms is under genetic control. That some environmental factors influence growth and ultimate size in organism is also a given. But the over-riding basis or limitation to size is genetic. That is why the Rubber Boa, regardless of age, never gets as large and some species of garter snakes, gopher snakes, indigo snakes, etc.

From both boas that have been maintained for long durations and from specimens recaptured over a long period of years, it is quite clear that once the species attains mature status, their growth rate declines markedly. In fact, I believe some of my data on recaptures on large, and thus old specimens shows growth becomes negligible and very close to zero.

That being said, prey consumption clearly plays a role in growth. The amount of prey consumed during a boa’s formative (non-adult) years is instrumental in 1) determining the length at which the snake reaches mature status and 2) likely determines its ultimate maximum length. But both of those factor have to be governed by the basic genetic composition of each species.

So a shorter active season at high elevations should have an impact. At the same time, existing evidence discounts the notion that the dwarf morph of the Rubber Boa is a result of such environmental conditions. The active season in the Lake Arrowhead region of the San Bernardino Mts. is likely similar to here in northwestern Oregon and certainly is longer than up in the Hyatt Lake region of SW. Oregon. Yet the boa population in the Hyatt Lake area get much larger than the boas in the San Bernardino Mts. and elsewhere in S. Calif. where the dwarf form occurs.

The information I have recorded on growth of captive specimens of both the dwarf and large morph phenotypes also supports the point that genetics, and not environmental factors are responsible for the two different size morphs in the Rubber Boa.

I have made some controlled crosses that establish that genes control the differences in the two size morphs. When a cross is made between a dwarf morph male and large morph female, only large morph neonates are produced. When the reciprocal cross is made between a large morph male and dwarf morph female, only dwarf morph neonates are produced.

From my perspective, the most interesting result are as follows:
From the first cross mentioned above, the one surviving hybrid female reach mature status at around the same length that large morph females reach mature status (over 22 inches). When backcrossed to either dwarf or large morph males, that hybrid female have only produce dwarf morph neonates.

From the reciprocal cross of large morph male X dwarf morph female, at this point, those F-1 females have yet to attain mature status. One female was born in 2010 and the other in 2008. The latter female was 8 1/8 when born on 8/25/08 and as of 6/22/15, was 14 7/8 inches. if what I have recorded thus far on all dwarf morph populations, she will need to be close to or a bit above 17 inches before she reaches mature status.

The F-1 hybrid female from the first cross above, dwarf morph male X large morph female, was born on 8/14/96, reached mature status at about 22 1/2 inches by 7/1/03, was backcrossed to a dwarf male in the spring of 2004, and produced her first litter on 8/5/04. She has since been backcrossed a couple of times to large morph males and regardless of which size morph male used in such controlled matings, she has only produced dwarf morph neonates. Such results support the inescapable conclusion that size is governed by genetic factors.

Now a sample of one is hardly conclusive, that being, this one hybrid female and the neonates she produces. Back in
2004, I made another cross between a dwarf morph male, this time from the Tehachapi Mts., with another local large morph female. That female produced 6 neonates that were all large morph in size. I gave that litter away to another herper.

In recognizing that the results from the first hybrid female could be simply due to chance, I asked that herper if I might barrow the largest female hybrid he still was maintaining. On 4/13/11, he loaned me his largest hybrid female that was an even 16 inches at the time. Local large morph females normally become mature at 22 inches and above. The female was a good feeder so by 6/16/12, she was at 22 3/8 inches and 23 1/4 inches by 10/8/12 and in the type of robust condition necessary to produce a litter the following year.

In April of 2013, I backcross that hybrid female to local large morph males and on 8/8/13, she produce a litter of 4 neonate which again, were all of the dwarf morph phenotype. In other word. those results were the same as what occurred with the first hybrid female.

I gave the female and 4 neonates back to the herper from which I had barrowed the female. Then early last year, I barrowed that hybrid females hybrid sister that had yet to attain adult status. By late summer last year, the second hybrid female had not yet reached adult status but her sister, the one I first barrowed had again reach the robust condition necessary to support a reproductive effort this year. So late last year, I barrowed that hybrid female again. She mated this spring to large morph males and if all goes well, should produce a second litter this late summer.

In the meantime, her smaller hybrid sister has reached mature status and now is in a robust condition. So I will hope to get a litter from her next year.

Richard F. Hoyer

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Re: SRB History / taxonomy

Post by Fieldnotes » July 25th, 2015, 1:38 pm

Okay, that idea was solved, they are genetically inclined to be dwarfs. There is no doubt you have been collecting a wealth of information on boas, and I certainly appreciate the deeper understanding of their natural history. - thanks Will

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 25th, 2015, 4:26 pm

Joseph:
In my opinion, there are two words that are over used and misused in wildlife agencies dealing with assessing non-game species of conservation concern, in the field of Conservation Biology, and elsewhere for that matter. They are the words ‘Expert’ and ‘Rare’.

I have never encountered anyone that could be considered an ‘expert’ in matters pertaining to individual species. There are certainly individuals that are authorities in particular species. Dr. Glenn Stewart and myself might be considered authorities on the Rubber Boa. But neither of us come close to being experts on the species.

I believe the term ‘rare’ can apply to two situations. The most common refers to a species whose numerical abundance is considered as exceedingly low and with extremely low densities. The term ‘rare’ can also refer to species with very small or restricted distributions. The Black Toad comes to mind.

But species having very small distributions but occupying suitable habitat at decent densities may not necessarily be rare in a numerical sense. They may be commonly encountered within their confined distributions.

But it is the former use, the perception that species are numerically ‘rare’ that is so badly misused. Years ago on the national PARC listserv web site, I wrote a series of mini-essays entitled “The Fallacy of Perceptions”. Herpetologists Travis Taggart and Dr. Harry Green understood and liked what I wrote, contacted me, and urged that those essays be combined and published.

Both gentlemen offered to help and it ended up with Travis Taggart undertaking that task. The opinion piece (let me emphasize ‘opinion’), was published March, 2007 in the Journal of Kansas Herpetology #21 under the above same title. And one of the three examples I cite is none other than the SRB scenario.

To get an idea of just how common can be the SRB, in the above article, I cite an example where in 2001, along with Brian Hinds (Fundad) and his then young son, when trying to find a pair of Calif. Mt. Kingsnakes for a researcher, we encountered 19 SRBs from about 10:45 AM to almost 6 PM. Clearly, conditions for encountering the species under surface cover objects that day were ideal. We did find a pair of mt kingsnakes, two gopher snakes, one ringneck snake and one W. Terrestrial Garter Snake along with the 19 SRBs.

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Re: SRB History / taxonomy

Post by Brian Hubbs » July 26th, 2015, 10:22 am

I would only have one disagreement with what you just said Richard. The word "rare" never applies to U.S. herps ever...We do not have any rare herps in the U.S. We have herps that are rarely encountered due to their secretive nature, but not rare herps. :thumb:

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Re: SRB History / taxonomy

Post by ricrabt » July 26th, 2015, 6:50 pm

Richard, thank you for your reports, and I will continue to work on the areas down my way. Also Danny and I have talked about Reyes and I have looked up there once before. I will try to plan a trip with Danny in a few weeks and we will keep you posted as to our results. As always it's a pleasure to help you out in any way I can. John L. /Ricrabt

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Re: SRB History / taxonomy

Post by FunkyRes » July 27th, 2015, 12:26 am

Response on subject of a "rare" US herp - off topic to this thread :

http://www.fieldherpforum.com/forum/vie ... 20&t=22355

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Re: SRB History / taxonomy

Post by FunkyRes » July 27th, 2015, 12:36 am

See above

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » July 27th, 2015, 4:06 pm

John L.
Unless you plan on driving the roads at night, trying to find the Rubber Boa during when it is dry in worm to hot during day time searches in August and Sept. is not likely to be productive. I would wait until it rains a couple of times and early morning temperatures come down possibly forcing boas to come up to surface objects to thermoregulate.

At this time of year, the boas likely can find their preferred temperature subsurface. But one never knows so good luck.

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Re: SRB History / taxonomy

Post by ricrabt » July 27th, 2015, 8:44 pm

Richard, I sent you a P. M...

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Re: SRB History / taxonomy

Post by CJJreptiles » August 7th, 2015, 12:31 am

Thank you very much for you post Richard. Fantastic write up. We all appreciate the hard work you put into your research.

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Re: SRB History / taxonomy

Post by jonathan » August 11th, 2015, 9:08 am

Incredible post. Thank you for this Richard.

All the information is astoundingly helpful. But the results of those hybrid crosses are just weird. Obviously need more data, but if it is true that hybrid females from dwarf mothers are large, but produce dwarf young, that would be a really odd result.

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » August 11th, 2015, 6:48 pm

Jonathon,
When large morph females are crossed with dwarf morph males, all neonates have been of the large phenotype.
When dwarf morph female are crossed with large morph males, all neonates have been of the dwarf phenotype.

It is the first cross above in which I have hybrid female that have reached mature status and produced litters. I have two female from the second cross above but they have yet to reach mature status.

However, the timing of your post couldn’t have been better. Last night, a hybrid, large morph female(Starker hybrid
female #5) produced a litter that adds one more example where such a hybrid female who herself if a large morph and has been back-crossed to large large morph males, only produces dwarf morph type neonates.

This particular female boa was one of 6 hybrids produced in 2004 from a mating between a local large morph female (Starker Pit female #32), and dwarf morph males from the Tehachapi Mts. I gave that litter of 6 hybrid neonates to a friend that maintains Rubber Boas. It usually takes about 8 years on the average to get female boas to reach mature status and at the time, I was already maintaining too many boas.

But then later, in seeking conformation of what had transpired with my first hybrid, large morph female (1996 cross between a local large morph female and dwarf morph males from the San Bernardino Mts.), that has only produced dwarf morph neonates, on 4/3/11, I barrowed this Starker hybrid female #5 when she was an even 16 inches hoping to get her to mature status in two years as my friend said she was a good feeder. Local large morph females reach mature status at around 22 inches, sometime a bit smaller but more often larger.

After the active seasons of 2011 and 2012, in Oct., 2012, this Starker hybrid female #5 had reached 23 1/4 inches and was in the type of robust condition necessary to produce a litter in 2013. She was mated to local large morph males and produced 4 neonates on 8/8/13, all of them of the dwarf phenotype.

I then asked to barrow her hybrid sister who was smaller as she wasn’t as good a feeder. I was hoping get this hybrid sister, Starker hybrid female #4, into reproductive status by last fall but that didn’t materialize as she had yet to reach the length and weight necessary to produce a litter this year.

But then, Starker hybrid female #5 had pigged out during 2014, was getting into reproductive condition again, so I barrower her again last August 31st. when she then measured 25 1/8 inches and was robust enough to produce another litter this year --- which is just what happened. Instead of 4 neonates, she produce 7 live neonates yesterday and still palps and 8th neonate. Whether or not she produces that last neonate is anyone’s guess.

This afternoon, I quickly measures all 7 neonates and they range between 7 3/4 or 7 7/8 inches to 8 1/4 to 8 3/8 inches, well within the range of lengths of neonates produced by dwarf morph females and well below the normal range of lengths of local large morph neonates (about 9 1/4 “ to over 11 “).

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Re: SRB History / taxonomy

Post by ricrabt » August 13th, 2015, 11:57 pm

Richard, what is the max length you've seen for a dwarf?

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » August 16th, 2015, 11:24 am

Up until recently, the maximum length I have observed of dwarf females was 22 1/4 inches. There was a boa that Robert Hansen (Herp. Review editor) captured on Breckenridge Mts. and retained for about 10 years that had grown to that length when I measured the boa many years ago. The female boa captured in 2012 on the Tejon Ranch also measured 21 1/4 inches. And a female from Mt. Pinos also measured 22 1/4 inches.

Then last year on 7/31/14, I received a very thin and very heavily scarred and old looking female that a herper found on the part of Mt. Pinos that is in Ventura Co. She weighed just 40.9 grams but was large, measuring 21 7/8 inches. I told the herper I would see if she would eat for me so that she would be in better condition to survive through the brumation period.

As it turned out, she did take enough meals so that by 10/3/14, she was in decent, average condition at 80.4 grams. I shipped the boa back to its owner this past March 10th. Now it was clear to me that this female boa had lost part of the end of her tail as it was badly scarred, her caudals only numbered 26, and her relative tail length (tail length divided by total length) was only 7.91%.

The average relative tail length of dwarf females is 11.1 %. So by applying that mean, female relative tail length to his particular female, without the tail shortened by injury, her estimated normal length would have been 575 mm or 22 5/8 inches making her the largest of the dwarf morph females yet to be discovered.

It would be highly unlikely that female represent the largest length dwarf female can attain. So it suggests that the dwarf form females likely can reach maximum lengths of 23 inches or thereabout.

The largest dwarf morph males record thus far was a 479 mm (18 7/8”) male from the San Bernardino Mts. and a 495 mm (19 1/2”) male from the Tehachapi Mts. So one might suspect that the largest dwarf morph males my attain a length of about 20 inches or thereabout.

Richard FH

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Re: SRB History / taxonomy

Post by ricrabt » August 16th, 2015, 5:27 pm

I sent you a pm...

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Re: SRB History / taxonomy

Post by NACairns » August 16th, 2015, 7:48 pm

Very interesting post and discussion. I'll have to look up the mtDNA papers but do these southern dwarf populations have low genetic diversity compared to the northern clade?
Regarding rarity, I was raised under the assumption that this species was rare in my native British Columbia but once I was able to drive found them to be the most common snake (at least at night) in number of my favorite places.
Thank you for the synopsis.
Best,
Nick

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Re: SRB History / taxonomy

Post by Richard F. Hoyer » August 17th, 2015, 7:11 am

Nick,
I do not believe any research has been performed that could provide an answer to your question about ‘genetic diversity’.

From past experience, amongst the herpetologists, conservationists, wildlife officials with which I have had contact in British Columbia, the prevailing mind-set is that the Rubber Boa is rare and of conservation concern.

I once made searches for the boa in the area near Creston. The habitat in that region is quite suitable for the species and I came up with a fair number of specimens in making daytime searches on parts of 2 or 3 days.

Favorable habitat for the species is extensive all across much of southern British Columbia from west to east. Why that does not resonated with individuals with biological backgrounds is a complete mystery to me!

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Re: SRB History / taxonomy

Post by NACairns » August 17th, 2015, 9:19 pm

It would be interesting to infer a demographic history for these populations and see what sort of growth patterns are reflected in the different clades and populations.

Creston is a great spot and as you say boas can be found in decent numbers.

As for BC, that does appear to be the tone and in fact the tone for Canadian herps in general. I think it is reflective of the spottiness of distributions at northern range limits and that being misconstrued as rarity. This is exacerbated by cryptic species like boas, western hognosed snakes or musk turtles. Complete regional surveys would take monumental effort by underfunded groups so spot checks are done and we move on. That said the spottiness does put the populations at higher risk of local extinction. My favorite boa road used to produce 3-5 a night 10 years ago but the area has been developed and car traffic from non-existent to regular every 5 min, now I'm lucky to see one. As such, I see why mangers are cautious.

Here is young one from the southern Okanagan a couple weeks ago.
ImageCharina bottae by N Cairns, on Flickr
Best,
Nick

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Re: SRB History / taxonomy

Post by Fundad » August 18th, 2015, 9:41 am

My favorite boa road used to produce 3-5 a night 10 years ago but the area has been developed and car traffic from non-existent to regular every 5 min, now I'm lucky to see one. As such, I see why mangers are cautious.
The reason your are seeing less, is most likely because,
1. Boas don't like light from traffic and turn away from road when there is traffic on it.
2. Artificial light from houses and such will often make the boas less likely to venture into the open during nighttime periods.

Fundad

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Re: SRB History / taxonomy

Post by NACairns » August 18th, 2015, 10:38 am

Here's hoping. I find the odd DOR there but much of the crown land is now private so I can't check the roadside habitat in many areas. There are still YOY.
Nick

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Re: SRB History / taxonomy

Post by Fundad » August 18th, 2015, 1:19 pm

I have many years experience in this kind of environment. And once you get away from the traffic and the lights, magically boas appear, in good numbers again.

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Re: SRB History / taxonomy

Post by hellihooks » August 18th, 2015, 4:32 pm

yeah... i learned that cruisen with Fundad... cruise the shoulders... NOT the road... :beer:

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Re: SRB History / taxonomy

Post by ricrabt » August 18th, 2015, 6:56 pm

Um you might want to look at the road as well. If your only looking at the shoulders ya might squish a poor little fella.... :crazyeyes:

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chris_mcmartin
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Re: SRB History / taxonomy

Post by chris_mcmartin » September 7th, 2015, 7:11 pm

Does anyone have any photographs of SRBs I could use in an article, based on Mr. Hoyer's post here and private correspondence? I'm giving it a home in the next SWCHR Bulletin (coming out at the end of the month) and have but one photograph from Mr. Hoyer himself.

If you have closeups of the heads (side and top both would be best) of both northern and southern boas, which I could use to point out scalation features, that would also be much appreciated. Of course, you will be credited for any photos used.

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ricrabt
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Re: SRB History / taxonomy

Post by ricrabt » September 9th, 2015, 9:03 pm

Pm me your email address. ..

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