Chilobrachys spermethecae

[Steve Nunn]

Hi,
This is a question for those of you with some knowledge of Chilobrachys spp. spermethecae.

Are there any other Chilobrachys spp. with the same spermethecal morphology as C.fimbriatus? Because I don't know of any and would expect any move to turn this species into a monotypic genus a big risk (as seperating any species into its own unique genus could be a bad move, from a phylogenetic aspect monotypic genera usually are not studied well enough to determine other species yet and are considered "not complete", there should in theory be congenerics) until further species could be allocated to the same genus.

I'm curious because this spider seems to be one of the more confusing members of this genus. I already know of opinions regarding seperating the Chilobrachys spp. based on significant variation, but am curious as to this one species??

Thanks,
Steve

 

[Tescos]

Hi Steve

Please bear in mind that I know next to nothing about taxonomy and the like, but could this maybe be one of those `gray area´ spiders which are kind of caught inbetween where one genus finishes and another genus starts. Abit like was or is the case with Brachypelmides and Brachypelma? I think I read that the genus Brachypelmides was created because of the differences of the spermatheca but was changed back to Brachypelma because it made things far too much confuseing or something like that as it was just the one character that was very different?

Could the same apply to Chilobrachys fimbriatus? or are there other major character differences to this species, that differ so much from the rest of the genus, so much so a new genus needs to be set up for it?

Like I said please bear in mind that I know next to nothing about taxonomy
or how it all works yeah so take my reply with a pinch of salt!
regards
Chris

 

[Steve Nunn]

Hi Chris,
LOL, well, you know something because you picked a great example, even though the subfamilies are quite different, basically the same principle applies.

You are also correct about Brachypelmides possessing possibly just the one character that would distinguish it as a seperate genus to Brachypelma. In "Brachypelmides" the spermethecae are bipartite, or not fused. In all other Brachypelma spp., the lobes are fused.

Also, Schmidt claimed to have noted scopula on femura IV of Brachypelmides, of course even though scopulation is a subfamily character for the Theraphosinae, none of the Brachypelma spp. possess it and this supposedly added weight to Schmidt's new genus. After examining the femura IV of B.klaasi and B.ruhnaui, Yanez et al. found only plumose setae and NOT scopula, Schmidt was in error.

Now, with such a strong character as the spermethecae, someone might argue that this indeed does warrant a new genus, even if only the one varying character was found. However, much needed to be considered before Schmidt could have created this new genus, such as geographical range, something he ignored. The range of the Brachypelma is only broken by Brachypelmides, in fact, considering morphology of its nearest relatives, each of the proposed Brachypelmides spp. seem closer related to other Brachypelma spp. then they do each other!!! For example regarding bulb morphology, B.ruhnaui is actually closer to Brachypelma vagans, then it is to B.klaasi, who's bulb morphology resembles the Brachypelma spp. on the Pacific Coast.

It should also be remembered that although these two genera were indeed synonymised, Yanez et al. stated that only through thorough phylogentic analysis this could best be determined, although they did suggest that the findings would be the same as theirs . Given that the homologous character of the Theraphosinae is the palpal bulb, as determined in the historic Theraphosinae revision, I would think Yanez et al. were indeed correct. As a point of interest, please look at the spermethecae of B.klaasi and compare it to the spermethecae of B.auratum, you would never see such different receptacles!! One looks like this \__/ (B.auratum), and the other, this \/ \/ (B.klaasi).

So, not in every case does such a strong character as the spermethecae and its varying morphology be the sole reason for a new genus, purely by these findings alone the evidence to support this is strong. Also, by geography alone it would be very difficult to show that B.klaasi represents an extreme form of this genus, as many others have stated, because the range of B.klaasi is not on the exterior of the Brachypelma range, but "inside" that of B.emilia, which is on the exterior (of the tight Brachypelma spp. populations within Mexico anyway). And the spermethecae of B.emilia are fused, just like the rest of the typical Brachypelma spp. This fact alone raises significant questions.

I have several species here from a new genus in Australia, these spiders share distinct characters of importance, there is no doubt. However, in one species, the spermethecae are fused, in the others, they are bipartite. Their spermethecal morphology differs more then I would have ever expected to see in the one genus. However, the deeper I look, the more I see the same findings in other members of the Theraphosidae.

While I would never argue the stability of the spermethecae for phylogentic or taxonomic research, there is evidence to suggest that variance is not all cut and dry, like once thought.

Thanks,
Steve

 

[FryLock]

Firstly Chris you swat .

Few ideas here I may be part guessing with, im thinking spermathecae was pushed back a little in it’s importance compared to say male papal characteristics (I think what you have stated from the paper is a great example of this) after cases like Brachypelma vs Brachypelmides obviously not the big differences like bilobular or unilobular (although I think there’s still both of those types found in a few subfamilies per as stated in the Perez Miles et al, tho that could have changed) but smaller differences like fused or only basely fused look like they can be given the slip at genus level so long as no other differences are present.

For example iv read that Davus was restored on more then just a fused spermathecae (thanks to Boris S for the info), but the real question is if any Chilobrachys.sp have a fully or even semi fused spermathecae at least in India for starters but then if anything was to turn up with such spermathecae but then also shared more with C.fimbriatus then any other known Chilobrachys.sp then of course it might be a case of new genus being needed other wise could the fused spermathecae be simpley viewed as very extreme autapomorphic state for C.fimbriatus :?.

 

[morda]

Hmm - most of Chilobrachys sp. spider are semi-arboreal. As far as I know Ch. fimbriatus is more like deep burrower.

 

[GoTerps]

Behavior is not in question here.

Does someone have pictures of various spermethecae from this genus?

I have ~10 C. fimbriatus but no other Chilobrachys.

 

[BakuBak]

No it isnt but in some casesys it may be healpfull when U have to choose , looking at beaviore U may get one more , final argument

 

[phormingochilus]

Chilobrachys hardwicki shares the same spermathecae morphology with C. fimbriatus, together with the abdominal patterning ... however the lyra is very similar but not as extreme as in C. fimbriatus. Leg lenghts to body ratio are different as well as size, natural habitat and distribution. C. fimbriatus is found in the SW of India and C. hardwicki in the SE and all the way into the bengal. These two species (and likely more of the indian species) are odd Chilobrachys species indeed, but the interesting question is the relationship between the type species C. nitelinus from Sri Lanka and the fimbriatus group and the andersoni group. Obvious differences can be pointed out in regards of spermathecae morphology in these three groups, but also very consistent characters that convincingly connect these three groups and makes the splitting/lumping question ever relevant ;-)

Regards
Søren

Hi,
This is a question for those of you with some knowledge of Chilobrachys spp. spermethecae.

Are there any other Chilobrachys spp. with the same spermethecal morphology as C.fimbriatus? Because I don't know of any and would expect any move to turn this species into a monotypic genus a big risk (as seperating any species into its own unique genus could be a bad move, from a phylogenetic aspect monotypic genera usually are not studied well enough to determine other species yet and are considered "not complete", there should in theory be congenerics) until further species could be allocated to the same genus.

I'm curious because this spider seems to be one of the more confusing members of this genus. I already know of opinions regarding seperating the Chilobrachys spp. based on significant variation, but am curious as to this one species??

Thanks,
Steve

 

[Steve Nunn]

Obvious differences can be pointed out in regards of spermathecae morphology in these three groups, but also very consistent characters that convincingly connect these three groups and makes the splitting/lumping question ever relevant

Hi Søren,
Yes, it does, doesn't it?? It can get very difficult when you come across such a strange geographical distribution for what may otherwise be considered a seperate genus. As mentioned before, Yanez et al. considered geography in the Brachypelmides synonymy, rightly so because geography weighs so heavily, natural distribution cannot and should not be ignored. Thankfully though, in the Brachypelma/Brachypelmides synonymy, the palpal bulb morphology added huge support to the geographical distribution of this genus.

If other confusing patterns in the Selenocosmiinae are anything to work with, then palpal bulb morphology may become even more important to this subfamily too.

@Fry, I'm getting more curious as to how the spermethecae morphology suits for generic placement, or even support. Specific or generic in these cases???? I really do not know..

Also, was it Boris who restored Davus??

Are there other cases of genera with huge variation in the spermethecae morphology?? What about for the entire infraorder Mygalomorphae??

Steve

 

[FryLock]

@Fry, I'm getting more curious as to how the spermethecae morphology suits for generic placement, or even support. Specific or generic in these cases???? I really do not know..

Also, was it Boris who restored Davus??

No it's Dr Schmidt’s work all the way Steve (others seem to hint that someone else was going to do it tho) but Boris gave a very nice translation at the T store of a large abstract which shows that Schmidt places them closer to Hapalopus then Cyclosternum based manly on the spermathecae (Mikhail pointed out that the one main spermathecae difference between Davus and Hapalopus that Dr Schmidt listed as being "seminal receptacles not as wide and low as in Hapalopus and more structured" is found between pentaloris and fasciatus) he does also say about the males of Davus having "Embolus similar to Hapalopus" i don't know if that means there's a apophysis near the embolus like Cyriocosmus or Hapalopus (or is H.butantan the only one with that character).

It would seem but he also brings in the tibial apophysis a lot, one of the characters Schmidt lists for Davus is "having a highly elongated primary segment of the tibial apophysis" which probably is not very important against some of the related genera (i.e. Metriopelma shares the fused spermo but no tibial spurs at all) i think is listed as being manly in relation to Hapalopus vs Davus males now I don't have Davus and Hapalopus males to look at myself only a front leg bitten off a male C.gaujoni by one of my females this shows one of the two segments to be roughly double the length of the other I would not have thought that counts as "highly elongated" but i don't know without a point of reference.

But common sense would dictate that with the huge difference in spermathecae even if the Davus apophysis was very much alike to Cyclosternum that could be discounted but knowing the spermo can be so variable even among species that fit nicely into genera on other characters it does not make it seem so cut and dried.

 

[Steve Nunn]

Hi Fry,
Hmmm, Schmidt, eeewwww.

He has his fingers in everything, doesn't he?? This group of spiders seems quite complex, I'm so not familiar with most spiders from that subfamily and tibial apophysis are far from what I know I try real hard to stick to just the Selenocosmiinae at this stage, I'm so far from understanding them (to my satisfaction anyway) that it bugs the living hell outta me, LOL

I know Schmidt has this wierd habit of producing decent work when he involves others heavily, I've talked about this with past workmates of his. Anything and virtually everything he has done by himself is just scary.

I have such a hard time understanding how he can describe new species, ressurrect old genera, create new genera, etc, etc... from this broad range of theraphosid subfamilies, the guy is anywhere and everywhere. I really feel that such detailed phylogenetic analysis needs to be performed firstly on the entire subfamily, by someone who can access all/ most of the rellevant types, prior to describing or ressurrecting genera, did he do that in this case? Or, perhaps it was obvious???

He recently worked with Haupt to ressurrect Yamia into the Selenocosmiinae and to be honest it seems like not too bad a job at all, interesting read if you can get hold of a copy. While not all types were examined in this case I think it wasn't needed, just examination of those types closest related to Yamia. Haupt, however has been a taxonomist for a long, long time with a broad range of experience with the entire Mygalomorphae, so, perhaps this is understandable. I dunno, I think there are still some obvious mistakes in this work too.

I think as with most of his work, there are more questions then answers in the end. Do you think the work is thorough??

Thanks,
Steve

 

[FryLock]

I have such a hard time understanding how he can describe new species, ressurrect old genera, create new genera, etc, etc... from this broad range of theraphosid subfamilies, the guy is anywhere and everywhere. I really feel that such detailed phylogenetic analysis needs to be performed firstly on the entire subfamily, by someone who can access all/ most of the rellevant types, prior to describing or ressurrecting genera, did he do that in this case? Or, perhaps it was obvious???

I agree there Steve im sure Dr Schmidt knows far more about taxonomy then some one with just a general interest in T's like myself but knowing how much reading and time and checking can go into even making sure you get genus right in some cases let alone species, it makes you think something is going to get dropped when you juggle so much data, I know that most ppl studying any group of organisms taxonomically tend only to look at one grouping at a time or at least only look at other groups when needed in reference to their main research.

As for Davus being obvious well only talking as some one that’s been round spiders a bit many ppl have called them Davus even a few years after the change was made which in a few cases could have been because they were slow on the change, but the few in resent years have iv heard those that use Davus put it down to spermo difference (as it's in one of Dr Schmidt's books i believe), i was away from T's for a long time (mid 90's until just over 2 years back) but real Cyclosternum.sp were no doubt thin on the ground until resent years (i have no strong memories other then the odd tub label which is no proof of the contents) and im sure then more ppl saw the differences for themselves (at least the spermathecae) when more true Cyclosternum.sp were around.

Rechecking the Cyriocosmus revision the female of H.butantan has a fair sized membranous base section of spermathecae before the sclerotized “heart shape” if this section is found in the all the other Hapalopus (the paper lists three and the end discussion seems to state it is so for the genus as a whole) and not Davus there’s another nice kind spermathecae difference even if the receptacles are very much alike other then the fused partly or unfused status.

 

[Steve Nunn]

Rechecking the Cyriocosmus revision the female of H.butantan has a fair sized membranous base section of spermathecae before the sclerotized “heart shape” if this section is found in the all the other Hapalopus (the paper lists three and the end discussion seems to state it is so for the genus as a whole) and not Davus there’s another nice kind spermathecae difference even if the receptacles are very much alike other then the fused partly or unfused status.

Hi Glen,
For sure, any variation in the spermethecae should be noted, if you're talking about the membranous area I think you're talking about then it is very flimsy at the best of times, can be very difficult at times to remove it whole from an exuvium, but yes, part of the receptacle morphology and if the variation is consistent, then it is worth noting. Character weighting is so important, that's why mapping every variation possible prior to any form of outgroup comparison is IMO paramount. I'm not talking about determining parsimony with a maximum no. of characters, no, no, no, just the mapping.

Ah well, the more cladistic analysis the better, we'll eventually sort it all out, LOL, right???

Steve