19.02.2022

Theraphosinae sp. "Piura" is definitely a Thrixopelma pruriens!!!

Some time ago we had expressed the assumption on our site that Theraphosinae sp. "Piura" is actually Thrixopelma pruriens ( = see HERE ). Unfortunately, when we compared them at the time, we only had two living males of both forms available. Both were anesthethized with CO2 at the time. An attempt was made to examine the bulbs at the correct and comparable angle for comparison with the most recent description of Thrixopelma pruriens [cf. Sherwood et al. (2021)]. However, the angle was not entirely correct.

Now we finally had two preserved males of both forms, so that we could repeat the study. But this time at the right angle for comparison with the publication by Sherwood et al. (2021). The result of the investigation that has now been carried out confirms our assumption at the time in an impressive way.

The comparison of the bulbs of both males (Pic 1, 2 & 3 = Thrixopelma pruriens; Pic 4, 5 & 6 = Theraphosinae sp. "Piura") shows an identical structural agreement. Both bulbs have an equally shaped "prolateral inferior keel" (PI) that shows an identical structure. The "Tegular heel" (TH) is also shaped in the same way. The tip of the embolus has the same shape in both bulbs and is rather short and broad. Both bulbs also show a high degree of structural agreement with the Thrixopelma pruriens bulb shown in the above mentioned publication by Sherwood et al. (Fig 7).

The shape of the spermathecae of Thrixopelma pruriens (Pic 8 ) and Theraphosinae sp. "Priura" (Pig 9) is almost identical, which is another indication of conspecificity. A comparison with the illustrated Spermathecae for Thrixopelma pruriens in Sherwood et al. (Pic 10) also shows a very close congruence of the spermathecae forms.

We wonder why one and the same species exists under different names in the community. Often dealers change the names of a tarantula species when sales are not going so well (see the different names for one and the same Chilobrachys species: Chilobrachys "burmensis", Chilobrachys bicolor, Chilobrachys huahini, Chilobrachys andersoni etc. -> Chilobrachys dyscolus). Could this business practice also be the reason for the different names of one and the same species in the present case?

Resumé:

By re-examining and comparing Thrixopelma pruriens with Theraphosinae sp. "Piura" there is no doubt that the so called Theraphosinae sp. "Piura" is a Thrixopelma pruriens Schmidt, 1998 due to the close structural similarities within the genital morphology of both compared males!

Reference:

Sherwood, D., Gabriel, R., Kaderka, R., Lucas, S. M. & Brescovit, A. D. (2021). Stabilizing a chaotic taxonomy: redescription and redefinition of the genera Lasiodorides Schmidt & Bischoff, 1997 and Thrixopelma Schmidt, 1994 (Araneae: Theraphosidae). Arachnology 18(8): 893-917.