Chisosa Huber, 2000

Huber, Bernhard A. & Carvalho, Leonardo S., 2019, Filling the gaps: descriptions of unnamed species included in the latest molecular phylogeny of Pholcidae (Araneae), Zootaxa 4546 (1), pp. 1-96 : 31

Chisosa Huber, 2000

Chisosa Huber, 2000: 124 ; type species by original designation: Pholcophora diluta Gertsch & Mulaik, 1941 .

Diagnosis/Description. See Huber (2000). The new species below fits the original diagnosis. No other New World genus combines small body size (0.8–1.4) with strongly enlarged male palpal femora (figs 483 and 490 in Huber 2000; Figs 105–106 , 110–111 herein). The male cheliceral armature is more variable among species than originally thought, but such variation in common among close relatives in Pholcidae and thus not unexpected.

Monophyly. The recent molecular phylogeny of Pholcidae ( Eberle et al. 2018) supports a sister group relationship between the type species Chisosa diluta (Gertsch & Mulaik, 1941) and the new species C. caquetio . However, no clear morphological synapomorphy is known to support the genus in its present composition. The widened male palpal femur was originally considered a potential synapomorphy ( Huber 2000), but at that time Chisosa was thought to belong to Ninetinae ; however, a widened male palpal femur is plesiomorphic for Arteminae . Similarly, the procursus is relatively complex when compared to other Ninetinae but not when compared to other Arteminae . It is unclear whether the small body size of Chisosa is a plesiomorphic or derived character.

Generic Relationships. The recent molecular phylogeny of Pholcidae ( Eberle et al. 2018) places the genus in “other Arteminae ” (i.e. Arteminae without Artema ) as sister to all other genera in this group; however, this sister group relationship receives low support.

Composition. The genus now includes three species: C. diluta (Gertsch & Mulaik, 1941) ; C. baja (Gertsch, 1982) , and C. caquetio sp.n..

Distribution. Known from Texas ( USA), Baja California Norte ( Mexico), and Curaçao and Aruba ( Netherlands Antilles).

Figures

FIGURES 105–109. Chisosa caquetio sp. n. (ZFMK, Ar 20619). 105–106. Left male palp, prolateral and retrolateral views. 107. Male chelicerae, lateral view. 108. Male prosoma, frontal view. 109. Cleared female genitalia, dorsal view. da, dorsal apophysis; gb, genital bulb; pr, procursus. Scale lines: 0.1 (107), 0.2 (105–106, 109), 0.3 (108).

FIGURES 110–116. Chisosa caquetio sp. n. (ZFMK, Ar 20618–19) and Pemona sapo sp. n. (ZFMK, Ven02/100-1 and Ar 20621). 110–111, 115–116. Males, dorsal and lateral views. 112–114. Epigyna, ventral views. Scale lines: 0.3 (112–114), 0.5 (110–111, 115–116).