Autor Thema: Assessment of Lycosa narbonensis  (Gelesen 165 mal)

Tobias Bauer

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Assessment of Lycosa narbonensis
« am: 2019-10-09 00:20:49 »
Hi together,

I write this post in English, so it's easier to read for our international members. In 2013, Planas et al. synonymized Lycosa tarantula with Lycosa narbonensis. The latter is now considered a junior synonym of L. tarantula. Although their analysis was based on four gene regions, there is something odd. The authors stated:

 The morphological differences between L. tarantula and L. narbonensis have never been clearly discussed and its distinction as separate species is mainly based on its supposed allopatry  [...] 

This is not true in my opinion. Simon discussed in his revision of the group (1876, plate 3 fig. 2 and 17 for epigynes) that there are clear differences in the epigyne (besides abdominal patterns) of both species:

L. narbonensis: L'épigyne plane, chagrinée, limitée par deux stries convergeant en arrière, terminée en arrière en pointe très-large dépassant à peine le bord de la plaque

L. tarantula: Pièce médiane de l'épigyne plane en triangle allongé.

And Simon also illustrated both epigynes, probably based on females from France and Italy, since he stated this countries as the solely distribution of each species. I think there has to be extreme intraspecific variations in one species to exhibit this kind of epigynal variation. Interestingly, when I have a look on Pierre's site, the epigyne of "L. tarantula" there from France fits well to the drawing of L. narbonensis in  Simon (1876 and 1937): https://arachno.piwigo.com/picture?/17366/category/450-lycosidae

Be also aware of that other illustrations of L. tarantula in the literature are probably based on Lycosa hispanica. As far as I know, only Simon illustrated "true" L. tarantula.

What do you think? Does somebody knows of material of true L. tarantula from Italy? Is there a possibility that a genetic differentiation between both species remained unknown because of the young age of Lycosidae in general and a relatively young origin (and maybe separation) of the French and Italian populations? Both "species" bug me for a while now, and I think this should be solved in the near future. Large Lycosids are probably sensitive to human disturbance and alien species, as we know from Hogna ingens, and their conservation should get much more attention.

Tobias
« Letzte Änderung: 2019-10-09 15:47:28 von Tobias Bauer »

Rainer Breitling

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Re: Assessment of Lycosa narbonensis
« Antwort #1 am: 2019-10-09 10:41:39 »
Hi Tobias,

I have always been astonished that there is hardly any documentation of Lycosa tarantula in the literature. It's the type species of the type genus of Lycosidae after all, and rather striking, in addition to being notorious since ancient times for its bite and all the folklore around this. I hope you will be able to provide some new insights here.

I haven't seen any specimens myself, but I would interpret Simon's figures slightly differently. Taken at face value, the epigynes as illustrated would not seem to belong to closely related species, not even to members of the same genus. To me that indicates a problem of artistic interpretation, rather than evidence of actual morphological differences. Planas et al. say that they examined the Lycosa material in the MNHN in Paris, and they should have noticed if there was a difference on this scale. If they didn't look carefully, they would not have been able to determine the large amount of material used for their study.

The genetic data seem to be solid, indicating that this is a single species, not a group of closely related species. If they only had done barcodes, one might be tempted to invoke this explanation, but not if there are four different markers, including nuclear genes. There also seems to be some geographic structure in the data, separating France, Northern Italy and Southern Italy, which would imply that the signal is true, and not influenced by weird introgression effects or incomplete lineage sorting.

Importantly, Simon himself describes intermediate specimens from the border region of France and Italy (Alpes-Maritime, Piedmont) as a subspecies cisalpina. This would further indicate that we are dealing with a single species, possibly with some geographically consistent intraspecific variation. The degree to which this variation is reproducible in larger samples and across the complete range would be extremely interesting to know. It's really astonishing that nobody seems to have published an analysis on this topic, and it would be great if you could make a first step in this direction. Ideally, of course, you might be able get hold of the specimens used by Planas et al. to start with...

Best wishes,
Rainer

Tobias Bauer

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Re: Assessment of Lycosa narbonensis
« Antwort #2 am: 2019-10-09 13:38:08 »
Hi Rainer,

thanks for the explanations. I don't know why nobody seems currently to work on this topic, as far as I know.

I Think one of the first steps should be to redescribe L. tarantula (including a Neotype from the type locality) from material in Italy and compare the specimens to material from France. Idealy, L. fasciiventris should be redescribed based on the material of Planas et al. collected at the type locality in similar situations as described by Dufour.

Tobias


Rainer Breitling

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Re: Assessment of Lycosa narbonensis
« Antwort #3 am: 2019-10-09 15:37:35 »
Planas and colleagues might actually be interested in collaborating on this. From their paper I get the impression that something like this may have been their original intention, but possibly a full taxonomic treatment with illustrations didn't quite fit with this journal. Some of their L. tarantula material comes from Pisa, about 60km west of the type locality in the mountains around Florence.
Best wishes,
Rainer

Tobias Bauer

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Re: Assessment of Lycosa narbonensis
« Antwort #4 am: 2019-10-09 22:47:04 »
This would be a nice project, maybe in 4-6 years, together with the Oxyopes lineatus/nigripalpis revision and the Alopecosa sulzeri-revsion  :P