Zoological Studies

Vol. 61, 2022

(update: 2022.9.15)

Description and Sexual Behavior of Two New Species of Mygalomorph Spiders (Araneae: Theraphosidae, Pycnothelidae), and First Record of Xenonemesia platensis (Pycnothelidae) of Corrientes, Argentina

Micalea Nicoletta1,*, Justina Panchuk1, Nicolás Peralta-Seen3, and Nelson Ferretti1,2,*

1Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, UNS), Camino La Carrindanga Km. 7, Bahía Blanca, Buenos Aires, Argentina. *Correspondence: E-mail: mmnicolettal@gmail.com (Nicoletta).
E-mail: panchukjustina@gmail.com (Panchuk); nferretti@conicet.gov.ar (Ferretti)
2Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, Bahía Blanca, Buenos Aires, Argentina
3Universidad Nacional de La Pampa, Facultad de Ciencias Exactas y Naturales, Av. Uruguay 151, Santa Rosa, La Pampa, Argentina. E-mail: nicolasperaltaseen@gmail.com (Peralta-Seen)

Received 10 September 2021 / Accepted 11 August 2022
Communicated by I-Min Tso

Paraje Tres Cerros is a low altitude hilly natural area surrounded by cattle fields and characterized by three isolated rocky formations of about 150–180 m a.s.l. located in Corrientes province, Argentina. Their topographic and environmental conditions are unique across the whole Mesopotamian littoral of Argentina and, therefore, can be considered as a biogeographic island that hosts several endemic species of plants and animals. The lack of knowledge of the mygalomorph spiders species of the area, led us to conduct a field study at Paraje Tres Cerros with the objective of surveying the mygalomorph spiders. From this survey, we described two new endemic species: Stenoterommata isa sp. nov. (Pycnothelidae) and Catumiri sapucai sp. nov. (Theraphosidae); and we recorded Xenonemesia platensis for the first time in Corrientes province. In addition, we described for the first time the sexual behavior for Stenoterommata isa sp. nov. and Catumiri sapucai sp. nov. Finally, we presented distribution maps for the genus Stenoterommata and Catumiri in Argentina and Xenonemesia platensis. Stenoterommata isa sp. nov. constitutes the eighth known species of the genus in Argentina and according to its distribution is the only exclusive species recorded in Corrientes province. Regarding its sexual behavior, we obtained one mating, which consisted in touches the female legs with legs I and II by the male, who starts the courtship by beating the female's cephalothorax and sternum with legs II and palps respectively. Then the male clasps with the first pair of legs between the palp base and chelicerae of the female and elevate her to reach the genital opening for the palpal insertions. Catumiri sapucai sp. nov. is the third species described from Argentina with a new spermathecae shape with two additional elongated digitiform domes external to the inner receptacles. We obtained five matings for this species, of which two, males contacted the females without an evident courtship and for the remaining three, the males initiated courtship by performing a few quick body vibrations. All males achieved the typical copulation position observed in most mygalomorphs and made about 3 to 5 palpal insertions, with the exception of one case in which spiders lost equilibrium and separated from each other. The presence of Xenonemesia platensis at this area is based on one adult female, thus further campaigns to collect more specimens will lead us to confirm this record or to better elucidate its taxonomic identity.

Key words: Taxonomy, Biodiversity, Tres Cerros, Catumiri, Stenoterommata.

Citation: Nicoletta M, Panchuk J, Peralta-Seen N, Ferretti N. 2022. Description and sexual behavior of two new species of mygalomorph spiders (Araneae: Theraphosidae, Pycnothelidae), and first record of Xenonemesia platensis (Pycnothelidae) of Corrientes, Argentina. Zool Stud 61:62.