Cyrtognatha quichua, Dimitrov & Hormiga, 2009

Dimitrov, Dimitar & Hormiga, Gustavo, 2009, Revision And Cladistic Analysis Of The Orbweaving Spider Genus Cyrtognatha Keyserling, 1881 (Araneae, Tetragnathidae), Bulletin of the American Museum of Natural History 2009 (317), pp. 1-140 : 40-44

Cyrtognatha quichua , new species Figures 1A–C, E, 3A, 11–14

TYPE: Male holotype from Ecuador, Napo Province, San Isidro, reserva Sierra Azul, 00 ° 40 9 S, 077 ° 55 9 W, 2300 m. 12.vi.1996, T.E. Erwin, fogging sample no. 1361 ( USNM).

ETYMOLOGY: Named after the Quichua, the major indigenous group in Ecuador. To be treated as a noun in apposition.

DIAGNOSIS: This species is very similar to the closely related species C. catia and C. pachygnathoides . It can be easily distinguished from C. pachygnathoides by the shape of the embolus, which is not widened subterminally. In C. catia the embolus is not widened but it is shaped as an ‘‘S’’ in ventral view (fig. 8A), while in C. quichua the embolus gradually curves toward the cymbium. C. quichua can be further distinguished from similar congeners by the presence of a semimembranous ridge on the embolus that reaches its tip (figs. 11A, 12D, 13A, C). The morphology of the male chelicerae is also very diagnostic. C. quichua has the strongest and the most divergent chelicerae compared to the other two species (figs. 11G, 12C).

DESCRIPTION: Male (holotype). Habitus as in figures 1A–C, 11G, H, 12A, B. Carapace brownish with a well-marked fovea. Abdomen brown-yellowish with numerous guanine spots and a conspicuous dorsodistal tubercle. Total length 4.50. Cephalothorax 2.45 long, 1.86 wide, 0.98 high. Abdomen 2.10 long, 1.57 wide, 1.96 high. Sternum 1.00 long, 0.98 wide. Clypeus height twice an AME diameter. All eyes nearly the same size except PME slightly larger. AME diameter 0.1. PLE– PME distance slightly more than twice one PME diameter. ALE and PLE juxtapose. Distance between AME equal to their diameter; between PLE half one PLE diameter. Chelicerae (figs. 11D, G, 12C, E, G) strong, slightly darker than the rest of the cephalothorax, with well-developed dorsal tooth distally. Dorsal cheliceral tooth curved, well developed, and very close to the joint of the fang. Femur I 4.90, twice the length of the cephalothorax. Epiandrous fusules as in figure 12F. Pedipalp as in figures 11A–C, 12D, 13A–F, I. Palpal tibia length 0.96; cymbium length 1.03. Male spinnerets as in figures 13A, B, G–H.

Female (paratype from the type locality). Coloration and general habitus as in male. Abdominal tubercle less developed than in male. Total length 8.33. Cephalothorax 3.43 long, 2.25 wide, 1.47 high. Abdomen 4.90 long, 1.56 wide, 4.00 high. Sternum 1.22 long, 1.21 wide. Clypeus height 1.3 times one AME diameter. Eyes as in male. AME diameter 0.09. Distance between PME equal to their diameter. Chelicerae less divergent than in male, with cheliceral teeth closer to each other. Femur I 5.29, 1.54 times the length of the cephalothorax. Vulva as in figure 11E, F. Median sac relatively small on the top of a high chamber.

Variation. Male cephalothorax ranges in length from 2.54 to 2.45 (n 5 4). Female cephalothorax is nearly the same in the two specimens studied (3.43). Male total body length ranges from 4.50 to 6.96 (n 5 4). Female total body length ranges from 7.35 to 8.33 (n 5 2). The male abdominal tubercle varies in height; in some specimens it is as high as the abdomen. Guanine spots vary in size; in some specimens the spots cover almost entirely the lateral and dorsal sides of the abdomen.

DISTRIBUTION: This species is known only from the type locality (fig. 5).

NOTES: The coloration of the abdomen in live specimens is greenish with some darker brownish patches and numerous silvery guanine spots (fig. 1A–C). It seems that the pigment responsible for the green color in vivo degrades rapidly when the specimens are stored in alcohol.

ADDITIONAL MATERIAL EXAMINED: Paratypes: ECUADOR: Napo Province – Sierra Azul , 00 ° 40 9 S, 077 ° 55 9 W, 2300 m. 1 female, 12.vi.1996, T.E. Erwin, fogging sample no. 1361 ( USNM) ; same locality, 13–15.vi.1996, G. Hormiga, 1 male ( SEM) ; same locality, 15.vi.1996, G. Hormiga, 1 male ; same locality, 13.vi.1996, G. Hormiga, 1 male, 1 female .