28.06.2024
Some Avicularia hirschii are not what they claims to be

A few days ago, Michał Królicki sent us some smaller exuviae and an adult male of a species of Avicularia that he had received from Ecuador under the name "Avicularia hirschii" (Pic. 1). In his opinion, these animals look different from the Avicularia hirschii sold by other Polish dealers. We were therefore asked to identify these Spiders, if possible. 

We used the large Avicularia revision by Fukushima & Bertani (2017) to identify this Avicularia species. As the exuviae contained spermathecae (Pic. 2), but did not come from adult females and are therefore hardly informative, we focussed on the identification of the adult male and used the identification key for Avicularia males in Fukushima & Bertani (2017) on page 40. 

Firstly, the length of the embolus in comparison to the tegulum is asked for in this key. As can be seen, for example, in the prolateral view of the bulb in the present specimen, the embolus is at least 4x as long as the length of the tegulum (Pic. 3). Thus it cannot be Avicularia hirschii Bullmer, Thierer-Lutz & Schmidt, 2006 , in which the length of the embolus is only 3.5 times the length of the tegulum. There are then very quickly only two species that can be considered, namely Avicularia caei Fukushima & Bertani, 2017 , which is native to Brazil, and Avicularia lynnae Fukushima & Bertani, 2017 , which also occurs in Ecuador. Because the "abdomen dorsum is equipped with a single longitudinal stripe and tegulum with developed prominence", only Avicularia lynnae remained. 

However, the species description in Fukushima & Bertani (2017) still had to clarify whether the characters of this species mentioned and shown also applied to the present male.

We photographed the bulb in the same positions as shown for the male of A. lynnae in Fukushima & Bertani (2017) on page 115 (Pic. 7). As can be easily recognised, the structure of the bulb and the shape of the embolus are virtually identical in all positions to the illustrations in Fukushima & Bertani (2017) (cf. Pic. 3 - 6 with Pic. 7). A comparison with the positions of the bulb of A. hirschii shown (Pic 8), however, shows clear differences in the shape of the bulb and the embolus.  Also, the "cluster of setae in apical portion, on prolateral side" in A. hirschi seems to consist of finer and lighter setae compared to A. lynnae (cf. Pic. 7 with Pic. 8). The setae of the present male are also thicker and darker (Pic. 9 - 11), just as can be seen in A. lynnae. 

In A. hirschii the metatarsus IV is half scopulated. In A. lynnae it is much less scopulated, as in the examined male (Pic. 12).

A. lynnae (Pic. 13) is also similar in general appearance to the examined male (Pic. 1).

Resumè:

Due to the high correspondence to the characters of Avicularia lynnae mentioned and shown in Fukushima & Bertani 2017, we are of the opinion that the alleged Avicularia hirschii of Michał Królicki is indeed Avicularia lynnae. However, whether this applies to all Avicularia hirschii in the tarantula community cannot be finaly clarified at the moment. However, there is a certain probability that other "Avicularia hirschii" in the hobby have been misidentified.

Reference: 

Fukushima, C. S. & Bertani, R. (2017). Taxonomic revision and cladistic analysis of Avicularia Lamarck, 1818 (Araneae, Theraphosidae, Aviculariinae) with description of three new aviculariine genera. ZooKeys 659: 1-185, Suppl. 1-5