Eukoenenia virgemdalapa, Souza, Maysa F. V. R. & Ferreira, Rodrigo L., 2012

Souza, Maysa F. V. R. & Ferreira, Rodrigo L., 2012, Eukoenenia virgemdalapa (Palpigradi: Eukoeneniidae): a new troglobitic palpigrade from Brazil, Zootaxa 3295, pp. 59-64 : 59-61

Eukoenenia virgemdalapa sp. n.

( Figs 1–15 )

Material examined. Holotype: adult female ( ISLA 1536) from Lapa Nova cave (UTM 23 299811 8010693), Vazante, Minas Gerais, Brazil, 18 Sept. 2009, leg. L. F. O. Bernardi. The specimen is deposited in the Coleção de Invertebrados Subterrâneos do Laboratório de Ecologia Subterrânea do Departamento de Biologia da Universidade Federal de Lavras ( UFLA), Lavras, MG, Brazil.

Etymology. The specific name virgemdalapa refers to the festival in honor of the Virgem da Lapa (the virgin of the cave, in allusion to the Virgin Mary, mother of Jesus), which occurs in Vazante since the 19th century and attracts thousands of visitors every year to the Lapa Nova cave.

Diagnosis. This species differs from all others of the genus Eukoenenia by the following combination of characteristics: presence of 7–8 blades in the prosomal lateral organs, frontal organs distally expanded, basitarsus IV with five setae, opisthosomal sternites IV–VI with a1, a2 and s, genital region of female with 10–11 pairs of setae on first lobe and 3+3 on second lobe.

Description. Prosoma. Frontal organ with two branches distally expanded, each 3.1 times longer than wide (35 µm/11 µm) ( Fig. 1 ). Lateral organ with 7–8, distally pointed blades, each 3.9–5.7 times longer than wide (39/ 10–40/7 µm) ( Fig. 2 ). Propeltidium with 10 + 10 setae in five rows ( Fig. 3 ). Metapeltidium with 3 + 3 setae: t1 (47.5 µm), t2 (100 µm), t3 (70 µm) ( Fig. 4 ). Deuto-tritosternum with at least four setae, but the full number could not be observed (obscured by leg II).

Chelicerae with four dorsal setae, two middle setae and one seta inserted near the tooth of the fixed finger ( Fig. 5 ). The number of teeth on the fingers of the chelicerae could not be precisely determined.

Legs. Basitarsus 3 of leg I 2.9 times longer than wide, with three setae (grt: 100 µm; r: 95 µm). Seta r as long as the segment (95 µm /95 µm, t/r = 1), inserted in distal half and reaching distal margin of basitarsus 4 (82.5 µm/ 60 µm, s/er = 1.3) ( Fig. 6 ). Leg I with 7 trichobothria in usual arrangement.

Leg IV: basitarsus 7.7 times longer than wide, with five setae (2 esd, 1 esp, grt and r), bta/ti 0.91. Stiff seta r 2.5 times shorter than the tergal edge of segment (174 µm/69 µm, t/r = 2.5) and inserted in its distal half (174 µm/ 117.5 µm, t/er = 1.4); esp and grt inserted in proximal half ( Fig. 7 ).

Coxal chaetotaxy: coxa I with 14 setae, coxa II with 3 thick and 10 normal setae, coxa III with 3 thick and 9 normal setae and coxa IV with 1 thick and 8 normal setae ( Figs. 8–11 ).

Opisthosoma. Tergite II–VI with 3 + 3 setae, two pairs of setae (t1, t3) between a pair of slender setae (s) ( Fig. 12 ). Sternite III with 2 + 2 setae. Sternites IV–VI each with 2 + 2 thickened setae in middle of opisthosoma (a1 and a2) between one normal slender seta (s) on each side (1+2 s setae on sternite VI, asymmetry caused by the presence of an additional s seta) ( Fig. 13 ); a pair of glandular pores can be observed between the a1 setae on these segments. Segments VII with 7 setae and segments VIII–XI with 8 setae each.

Only two flagellar segments were found with the specimen in the tube. The first has two short setae and eight long setae and the second has nine long setae. In addition, each segment has setae similar to spikes at the apex ( Fig. 14 ).

Female genitalia. First lobe with 10 + 11 setae (asymmetry caused by dislocations due to lack of regular seta or presence of additional seta) in 5 transverse rows: 4 sternal 2 + 2, 2 + 2, 1 + 2, 1 + 1 and distal 4 + 4, of which a1, a2, a3 and a4 measure 17, 18–20, 22–27 and 40 µm respectively. Second lobe with 3 + 3 setae (x, y, z), measuring 27, 38 and 32 µm respectively; 5 glandular orifices ( Fig. 15 ). The mouth of the spermatheca illustrated in figure 15 (other parts of spermatheca could not be observed).

Measurements (in μm). Body. Total length 1670; dorsal shield length 340.

Pedipalp. Tibia 172.5; basitarsus 1, 70; basitarsus 2, 77.5; tarsus 1, 45; tarsus 2, 62.5; tarsus 3, 75. Leg I. Tibia 177.5; basitarsus 1 + 2, 142.5; basitarsus 3, 95; basitarsus 4, 67.5; tarsus 1, 50; tarsus 2, 50; tarsus 3, 172,5.

Leg. IV. Tibia 190; basitarsus 1, 174; tarsus 1, 167.5; tarsus 2, 92.5; width of basitarsus IV at level of seta r 22.5; distance between base of basitarsus IV and insertion of seta r 117.5; length of tergal seta (grt) 87.5; length of stiff seta (r) 69; ratio between length of basitarsus IV and stiff seta length (t / r) 2.5; ratio between length of basitarsus IV and distance to insertion of stiff seta (t / er) 1.48; ratio between lengths of prosomal shield and basitarsus IV (B/bta) 1.9; ratio between lengths of basitarsus IV and tibia IV (bta/ti) 0.91.

Habitat. Lapa Nova is a dolomitic cave located in the municipal district of Vazante, Minas Gerais, Brazil. This cave has approximately 4.5 km of linear development and receives a large number of tourists during a religious festival in honor of the Virgem da Lapa (virgin of the cave), which occurs early in the month of May. The specimen described here was collected in an area not subject to visits by tourists. Several biospeleological surveys were conducted in the cave during the past years, and only one specimen was found. This clearly shows the rarity of the species.

Figures

FIGURES 1 – 7. Eukoenenia virgemdalapa sp. n. 1, frontal organ; 2, lateral organ, dorsal view; 3, propeltidial chaetotaxy; 4, metapeltidial setae; 5, left chelicera; 6, basitarsus 3 – 4 of leg I; 7, basitarsus IV. Scale bars: 40 µm (Figs 1 – 2), 60 µm (Fig. 4), 80 µm (Figs 6 – 7), 200 µm (Figs 3, 5).

FIGURES 8 – 13. Eukoenenia virgemdalapa sp. n. 8, coxa I; 9, coxa II; 10, coxa III; 11, coxa IV; 12, opisthosoma, dorsal view; 13, opisthosoma, ventral view. Arrows in figures 9 – 11 indicate thick setae; those in figure 12 indicate setae displaced from original positions. Dotted line in figures 12 – 13 indicates plane of symmetry. Scale bars: 100 μm (Figs 8 – 11), 500 μm (Fig. 12 – 13).

FIGURES 14 – 15. Eukoenenia virgemdalapa sp. n. 14, flagellar segments; 15, female genitalia. Scale bars 250 μm (Fig. 14) 100 μm (Fig. 15).