Acheroxenylla lipsae

Description of the cave. The type locality is Cueva de Samuel. Collecting was done 200 m from the entrance on Guacharo guano, where was the new species found. It is an active cave with water flowing from the cave. The air temperature was 15 ° C. Its entrance is about 1,720 m a. s. l. In the first part of the cave there is a gallery with a colony of oil birds (Guacharos, Steatornis caripensis Humboldt, 1817). 500 m deep in the cave there is a big room with many big stalagmites, named Chachapoyas room. There are two small waterfalls, a small at 800 m from entrance and more far another of 10 m. One of the tunnels finishes in a well of more than 40 m.

Description. Body length (average of 7 specimens) = 1.25 mm. Setae not differentiated in macro and microsetae, all smooth and sharp mesosetae about 11 μm with small barbulations. Sensorial setae longer than regular setae, about 30 μm. Sensorial formula as 022 / 11111. Color, some specimens (Figures 1, 2) with very dark eyespots; others gray with small patches of blue color on body and black eyespots (Figures 3, 4). Cuticular granulation strong, Yossi's parameter 5 or 6. Ratio of head: antenna = 1: 0.8 labrum formula: 2 / 5,5,4. Ant I with seven dorsal setae, Ant II with 12 setae. Ant III with 17 setae in two whorls, sense organ with two free club-shaped microsensilla, not covered by tegumentary fold; two short guard sensilla (Sgd and Sgv) of same shape and size, and one ventral microsensillum. No eversible sac between Ant III-IV. Ant IV with four cylindrical sensilla, one dorsal and three latero-external; subapical organite, lateral microsensillum and simple subapical bulb (Figure 5), no sensory file on ventral side. Ratio of Ant I: II; III-IV = 1: 1.1; 1.4; 3.8. Head with typical chaetotaxy for the genus, similar to Xenylla, only 3 subdorsal setae, seta c 1 and only 1 setae v (v 1), and 3 subequal setae in ocular area (Figure 6). 2 + 2 eyes of about equal diameter with very strong granulations of dark pigment. PAO absent. Labium with 4 + 4 setae (one longer than others); 3 pairs of postlabial setae. Mandible with 3 - 4 apical teeth, and normal molar plate. Maxilla with six lamellae. Th I with 3 + 3 dorsal setae and 1 + 1 lateral on upper subcoxae. Each Th II and III with 3 irregular rows of setae (Figure 8), sensorial setae m 6 and p 4 as usual. Leg chaetotaxy from I to III: precoxae 0,1,2; coxae 3,6 - 8,5 - 8; trochanters 5,5,4; femora 12,11,10 one ventral seta very long, as acuminate tenent hair; Tita 19,19,18 (Figures 7, 9); pretarsi 2,2,2. Two dorsal tenent hairs weakly clavate on dorso-distal whorl on Tita I and II; one on Tita III. Unguis thin, elongated, curving slightly, without any tooth (Figures 7 - 9). No unguiculus. Ratio Tita / unguis = 1: 1. Dorsal chaetotaxy of abdomen as in Figure 10. Abd I-III with 2 irregular rows of dorsal setae, 1 sensorial seta on P 5, except Abd V with p 3 as sensorial seta. Number of axial setae from Abd I to III is 2 + 2: Abd. IV with 3 + 3; Abd. V with a 1 and a 2, p 3 is ss. Abd VI with 2 rows of setae, a 1 - 3, p 1 modified as spine, p 2 - 3 normal setae. Two small anal spines, as short as their tubercle. Ventral chaetotaxy. Thoracic sternites and Abd I without setae. Ventral tube with 4 + 4 setae. Abd II with 9 - 12 setae, one of them (p 3) very long; Abd III with 6 setae, p 3 slightly longer than others. Abd IV dorsolateral with 5 setae, one of them very long (Figure 10). Retinaculum with 3 + 3 teeth, without seta on corpus (Figure 10). Furcula well developed. Manubrium with 3 pairs of setae of same length. Dens dorsally with moderate granulation and with 2 subequal setae, with a smooth elongated area on anterior part of dens. Mucro more than the half-length of dens, long and narrow with one small outer lamella, apex curved and more sclerotized (Figure 11). (Ratio Manubrium: dens; mucro = 1: 0.8; 0.5). Mucro better delimited on anterior part by a clear notch (Figure 12). Genital plate of female with 3 + 3 pregenital, 10 - 13 circumgenital and 1 + 1 eugenital setae. Genital plate of male with 3 + 3 pregenital, 44 circumgenital and 4 + 4 eugenital setae. Each anal valve with 13 regular and 1 hr setae.

Description. Holotype female (number FC-UNAM 22501) and one paratype female (numbers FC- UNAM 22502) are kept at Dept. Entomology; Museo de Historia Natural, Universidad Mayor de San Marcos, Peru; two paratypes females one male and one juvenile (numbers FC-UNAM 22500, 22503 to 22325) are kept at Mexican Collembola collection at Facultad de Ciencias, UNAM.

Diagnosis. Acheroxenylla lipsae sp. nov. is characterized by the presence of a well-developed furcula with mucro, long dente with two long dental setae each, three manubrial setae and a retinaculum with three teeth. Tibiotarsi are longer than in other species known.

Discussion. This new species is the largest and most pigmented member of this genus. The main differences of Acheroxenylla lipsae sp. nov. and the other species is the presence of a well-developed furcula with mucro, long dens and two long dental setae, 3 + 3 manubrial setae and retinaculum with 3 + 3 teeth. A. furcata has a reduced furcula, with no manubrial setae, very short dens with one seta each and mucro absent; its retinaculum has only two teeth on each ramus. The type species A. cretensis and A. canariensis lack completely the furcula and retinaculum. All the species have only two eyes per side; nevertheless, in the new species A. lipsae sp. nov., eyes are better developed and closer to each other, and that is why their position seems to be " D " and " E ". After the drawings of Ellis (1976), the eyes of A. cretensis are " B " and " E "; as pointed by Ellis (1976): " only 2 + 2 eyes small, widely separated ocelli ". Another difference is that A. cretensis has only 2 subdorsal cephalic setae, while the new species has 3 pairs, setae sd 5, sd 4 and sd 3, similar to A. furcata. There are small differences in the head chaetotaxy, A. lipsae sp. nov. has cephalic setae a 0, as A. cretensis. About the pigment, A. furcata is white with small spots under each of the 2 + 2 or 1 + 1 eyes and sometimes a scattered bluish gray pigment is present all over the body, while A. lipsae sp. nov. is more pigmented. Tibiotarsi of A. furcata with one apical tenent hair (A 1), sometimes weakly clavate, is similar to the new species. The ungues of the Peruvian species is more elongated than in any other species of the genus (ratio tibiotarsus: ungues: 1: 1.0), so this may be a troglomorphic character, and also in the other species tibiotarsus is about twice the length of ungues.

Etymology. This species is dedicated to Josiane Lips, for her contribution to the knowledge of cave fauna from Peru, Mexico and many other places.