Sinamma Lin & Li

Lin, Yucheng & Li, Shuqiang, 2014, New cave-dwelling armored spiders (Araneae, Tetrablemmidae) from Southwest China, ZooKeys 388, pp. 35-67 : 36

Sinamma Lin & Li gen. n.

Type species.

Sinamma oxycera sp. n. from cave of Guangxi, China.

Etymology.

The generic name derives from the Latin word “sina” and “-mma” as a suffix of the genus Tetrablemma . The gender is feminine, with sina meaning China.

Diagnosis.

Sinamma gen. n. differs from all known genera of Tetrablemminae by the presence of a tubercle on the male carapace (Figs 1G, 1E; Lin and Li 2010: 24, figs 19, 20) and sometimes in females (Figs 1H, 1F; Lin and Li 2010: 25, figs 25, 26), the strongly modified male leg I (Figs 2 C–E; Lin and Li 2010: 24, fig. 22), and by the exceptionally narrow postepigastral scutum in the both sexes (Figs 1B, 1D, 3 A–C, 19B; Lin and Li 2010: 25, figs 27-28).

Description.

Small (1.2-1.6), six eyes compact in a group, male carapace usually with cephalic tubercle (present or absent in female). Male leg I robust, with tubercles at tibia and metatarsus. Cheliceral horn present (absent in female), much longer than in Brignoliella Shear, 1978 or Shearella Lehtinen, 1981, but shorter than in Tetrablemma O. P.-Cambridge, 1873 and Gunasekara Lehtinen, 1981. Abdomen oval, lateral scuta II–IV wide in both sexes.

Bulb long pyriform, embolus simple, needle-shaped; epigynal fold narrow; postepigastral scutum exceptionally narrow; central process absent, inner vulval plate well developed, vulval stem transverse.

Remarks.

The new genus Sinamma gen. n. contains two species and belongs to the subfamily Tetrablemminae . Sinamma gen. n. is similar to Shearella by the conical cheliceral horn and the pyriform bulb in the males, and is also similar to Gunasekara in having strongly modified leg I in the males. However, it can be distinguished from both Shearella and Gunasekara by the carapace having cephalic tubercle in male (sometimes in female also, e.g. Sinamma oxycera sp. n. and Shearella sanya Lin & Li, 2010), the presence of a distinct inner vulval plate in the female, and by the exceptionally narrow postepigastral scutum. The only oriental genus, Singalangia Lehtinen, 1981, for which the male is not yet known, has entirely different ocular pattern and vulval structures compared with those of Sinamma gen. n. In summary, Sinamma oxycera sp. n. and Shearella sanya Lin & Li share the following synapomorphies: an obvious cephalic tubercle, a strongly modified leg I in the male, and an exceptionally narrow postepigastral scutum in the female. These features distinguish them from other tetrablemmids. The new genus Sinamma is therefore proposed to accommodate these two oriental species, Sinamma oxycera sp. n. and Sinamma sanya (Lin & Li, 2010), comb. n., previously considered in Shearella .

Composition.

Sinamma oxycera sp. n. and Sinamma sanya (Lin & Li, 2010).

Distribution.

China (Guangxi, Hainan).