Eukoenenia mocororo, Souza & Ferreira, 2022

Souza, Maysa Fernanda Villela Rezende & Ferreira, Rodrigo Lopes, 2022, Eukoenenia mocororo (Palpigradi: Eukoeneniidae): a new troglobitic palpigrade from a Brazilian ferruginous cave, Zootaxa 5213 (5), pp. 497-512 : 498-507

Eukoenenia mocororo sp. n.

Material examined. Holotype, male (ISLA 13157): Brazil, Minas Gerais, Rio Pardo de Minas, Mocororô Cave (890 m. a.s.l, 16°0′36.72″S, 42°42′12.96″W), 22/II/2015, leg. R. L. Ferreira . Paratypes (all collected at the same locality as the holotype) : two females ( ISLA 13158, ISLA 13159) , one immature B ( ISLA 13160) and one immature C ( ISLA 13161), same data as the holotype ; one immature A ( ISLA 101121) and one female ( ISLA 101122), 10/IV/2016, leg. R. L. Ferreira ; one female and one male ( MZSP 49204 ), 27/ II /2012, leg. Pellegatti et al .

Diagnosis. Frontal organ with two reticulated branches with rounded tips; five blades finely reticulated in the lateral organs; 5 setae on deutotritosternum; 10 pairs of setae on propeltidium; 3 pairs of setae on metapeltidium (t 2>t 3>t 1); cheliceral fingers with 9 teeth each; pedipalp coxa with 18 setae; coxal formula 3,3,1; 6 setae (grt, gla, r, esp and 2 esd) on basitarsus of leg IV; opisthosomal tergites II–VI with two pairs of setae t between one setae s on each side; opisthosomal sternites IV–VI with two pairs of a setae flanked by one seta s on each side; first lobe of male genitalia with 14 pairs of setae (2 st +10+2 fusules on each half), second lobe with 5 pairs of setae and third lobe with 4 pairs of setae; first lobe of female genitalia with 10 pairs of setae.

Description of adults

Body length without flagellum: 980–1275. Measurements and ratios of adult specimens are given in Table1 .

Prosoma. Frontal organ (35) formed by two reticulated branches with rounded tips ( Fig. 1A ). Lateral organ with five blades (20–30) pointed-lanceolate and finely reticulated ( Fig. 1B ). Propeltidium with 10+10 setae ( Fig. 2A ). Setae t 1, t 2 and t 3 of metapeltidium 50–68, 98–105 and 75–77 long, respectively. Labrum with 5+5 short setae. Deuto-tritosternum with 5 setae in U-shaped arrangement. Basal segment of chelicera 220–237 long (dorsal length), with 6 proximal setae (p 4 and p 6 thickened and densely barbed in their distal third) ( Fig. 1C ), 3 distal setae: d 3 (102–115) smooth near base and with tiny projections in its distal half, d 1 (50–57) and d 2 (55–62) robust and with tiny projections in the truncated apex (d 1 slightly thinner than d 2) ( Fig. 1D ); and 1 apical seta. Hand of chelicera with 7 setae: 4 dorsal setae, 2 setae in its outer portion (1 close to articulation of movable finger and 1 on a tubercle close to the teeth of the fixed finger) and 1 seta inserted in its inner portion. Fingers with 9 teeth each.

Coxal chaetotaxy. Pedipalp coxa with 18 setae ( Fig. 2B ); coxa I with 13 ordinary setae and 2 microsetae ( Fig. 2C ); coxa II with 3 thick, 2 macrosetae and 8 ordinary setae ( Fig. 2D ); coxa III with 3 thick, 1 macroseta and 8 ordinary setae (including 1 small seta adjacent to macroseta) ( Fig. 2E ), and coxa IV with 1 thick and 8 ordinary setae ( Fig. 2F ).

Palp. tc with 9 setae; fe with 8 setae; ti with 9 setae (8 setae on right ti of male I) ( Fig. 3A ); bta1 with 2 m and 1 normal seta; bta2 with 2 normal setae and 4 m; ta1 with 2 m; ta2 with 5 m and 1 normal seta ( Fig. 3B ); ta3 with 1 fs (branches with similar lengths), 1 cs with a basal spine, 2 r, 12 m (one of the macrosetae with a conspicuous spine) and 8 normal setae ( Fig. 4A ).

Leg I. tc with 13 normal setae, two of which are considerably smaller than the others; fe with 9 normal setae; pa with 9 normal setae and 1 tb; ti with 9 normal setae ( Fig. 4B ); bta1 with 1 normal seta, 1 m, 2 tb and 1 fs (with the inner branch shorter than the outer branch); bta2 with 3 m, 1 normal seta, 2 tb and 1 fs (with the inner branch shorter than the outer branch); bta3 with 1 r, 1 grt and 1 short seta; bta4 with 5 m, 1 tb and 1 f s (with the inner branch shorter than the outer branch); ta1 with 5 normal setae (one considerably smaller than the others); ta2 with 5 m, 1 tb and 1 fs (with the inner branch shorter than the outer branch) ( Fig. 4C ); ta3 with 5 f s (branches with similar lengths) arranged as fs 1 / fs 2 / fs 3 / fs 4+5, rs (rs / fs 1 = 2.9–3.5), 2 r, 1 cs, 13 m and 5 normal setae ( Fig. 4D ).

Leg II. tc with 3 normal setae; fe with 5 normal setae; pa with 1 m, 1 thick seta, and 3 normal setae; ti with 1 thick seta and 4 normal setae; bta with 6 normal setae; ta with 1 r, 1 m (with a conspicuous spine) and 9 normal setae.

Leg III. tc with 2 normal setae; fe, pa, and ti with 1 thick seta and 4 normal setae each; bta with 1m and 5 normal setae; ta with 1 r, 1 m (with a conspicuous spine) and 9 normal setae.

Leg IV. tc with 3 normal setae; fe with 3 normal setae; pa and ti with 1 thick and 4 normal setae each; bta with grt, r, esp, and 2 esd; ta1 with 4 normal setae; ta2 with 8 normal setae.

IVbta. 5.6–6.8 times longer than wide and with 6 setae (grt, gla, r, esp and 2 esd). Seta r 2–2.26 times shorter than the tergal edge of segment and inserted in its distal half (d r / IVbta =0.55– 0.6); esp, gla and grt inserted in proximal half: grt and gla are inserted approximately at the same level, esp setae located basally from grt and gla ( Fig. 5A ).

Opisthosoma. Tergites II–VI with 3+3 dorsal setae, two pairs of t setae (t 1, t 2) between a pair of slender setae (s) ( Fig. 7A ). Sternite III with 2+2 setae. Sternites IV–VI each with 2+2 thickened setae (a 1, a 2) between a pair of slender setae (s) inserted caudal to the thick setae; a pair of pores present between a 1 setae on sternites IV‒VI. Setae a in the sternites IV–VI of male (60–72 long) and females (50–55 long) with similar shape, becoming gradually thinner from the base to the apex ( Figs 5B , 7B–C ). Segments VII–XI with 8 setae each. The dorsal (15–32 long) and ventral (12–27 long) setae on intermediate ring of the flagellum with similar lengths. Pubescence of the opisthosomal segments IX–XI evenly short and dense.

Male genitalia. 14+14 setae: 2+2 anterior (st 1, st 2) setae close to first lobe and 12+12 setae (11 setae on the right side of the male holotype; asymmetry caused by the lack of a regular seta) in the first lobe (including 2+2 fusules). Fusules close to each other, with a dilated conical base, a setiform end and internal canals. Each half of second lobe subtriangular, with a simple apex and 5 setae (4 setae on the right side of the male holotype; asymmetry caused by the lack of a regular seta). Cuticular orifices not observed. Each half of third lobe also subtriangular, with a bifurcate tip and 4 setae (w, x, y and z) ( Fig. 6A ).

Female genitalia. First lobe with 10+10 setae in 5 transverse rows: 2+2 sternal setae (st 1, st 2) followed by 2+2, 1+1, 1+1 and 4+4 distal setae (a 1 = 16–17, a 2 = 19–20, a 3 = 27–32, a 4 = 27); inner surface of the first lobe with a group of 3 orifices on each side and a medial pair of smaller orifices. Second lobe with 3+3 setae (x = 17–21, y = 39, z = 29–32); presence of cuticular spines and a group of 4 orifices on each half ( Fig. 6B ).

Flagellum. Present only in the female IV ( ISLA 101122): filiform, slightly longer than body length (1155) and formed by 14 segments. Segments 1, 2, 3, 5, 7 and 9 with an apical crown of spikes. The setae in segments I–XI are inserted in distal half, in the segment XII they are inserted in the middle and in the segment XIII they are inserted in proximal half. Number of setae and length of flagellar segments I–XIII: 8 (92), 9 (92), 9 (92), 8 (95), 8 (52), 8 (97), 8 (70), 8 (102), 7 (80), 8 (117), 7 (92), 8 (120), 8 (82). Last segment (50) with seven setae inserted in its proximal half and one terminal seta ( Figs 7D–F ).

Description of immatures

Body length without flagellum: 865–1060. Measurements and ratios of immature specimens are given in Table 2 .

Immature A. Lateral organs with three blades. Labrum with 3+3 setae. Deuto-tritosternum with 1 seta. Chaetotaxy of metapeltidium, propeltidium and basal segment of chelicera complete. Hand of chelicera with 5 setae: 2 dorsal setae, 2 setae in its outer portion (1 close to articulation of movable finger and 1 on a tubercle close to the teeth of the fixed finger) and 1 seta inserted in its inner portion. Fingers with 7 teeth each. Coxal chaetotaxy: pedipalp coxa with 17 setae, coxa I, II and III as in adults and coxa IV with 5 ordinary setae. Chaetotaxy of most segments of palp and leg I similar to that of adults, except for the following differences: P ti with 8 setae, P bta1 with 1 m, P ta1 with 1 m, I ti with 8 setae and I bta1 with 1 fs. IVbta with 3 setae (r and 2 esd); seta r inserted in the distal half. Chaetotaxy of opisthosomal tergites II–VI and segments VIII–XI similar to that of the adults. Segment VII with 6 setae. Sternite II with 2+2 setae. Sternite III with 3+3 setae (the central pair much shorter than the others). Sternites IV–VI each with 2+2 thickened setae (the slender setae are absent).

Immatures B and C (juvenile female and male, respectively). Lateral organs with three blades. Labrum with 4+4 setae. Deuto-tritosternum with 3 setae. Chaetotaxy of metapeltidium, propeltidium and basal segment of chelicera complete. Hand of chelicera with 6 setae: 3 dorsal setae, 2 setae in its outer portion (1 close to articulation of movable finger and 1 on a tubercle close to the teeth of the fixed finger) and 1 seta inserted in its inner portion. Fingers with 8 teeth each. Pedipalp coxa with 17 setae. Chaetotaxy of coxae, of articles of palp and leg I, of IVbta and of opistossoma (except for the sternites II and III) as in adults.

Primordia of genital lobes of immature C: the anterior genital lobe in sternite II comprises two halves with 7 pairs of setae in 3 transverse rows: a proximal pair of setae, followed by 2+2 setae and more distally by 4+4 setae. The two halves of the second lobe, also in sternite II, is flanked by a pair of setae ( Fig. 6C ); 2+2 setae on each side of the third lobe on sternite III.

Primordia of genital lobes of immature B: the anterior genital lobe in sternite II comprises two halves with 4 pairs of setae in 3 transverse rows: a proximal pair of setae, followed by 2+2 setae, and a pair of distal setae; presence of a pair of short apical spines in the first lobe. The posterior lobe also comprises two halves, flanked by a pair of setae ( Fig. 6D ). Sternite III with 2+2 setae on each side.

Etymology: the specific name mocororo refers to the name of the cave where specimens were found. The name is to be treated as a noun in apposition.

Figures

FIGURE 1. Eukoenenia mocororo sp. nov. A, frontal organ (paratype, ISLA13158); B, blades of lateral organ (paratype, ISLA13158); C, proximal setae (p1–p6) on basal segment of chelicera (holotype); D; distal setae (d1–d3) on basal segment of chelicera (paratype, ISLA13158). Scale bars 20 μm.

FIGURE 2. Eukoenenia mocororo sp. nov. A, propeltidial chaetotaxy (paratype, ISLA13159); B, coxa of palp (holotype); C, coxa of leg I (holotype); D, coxa of leg II (holotype); E, coxa of leg III (holotype); F, coxa of leg IV (holotype). Black arrows in figures F–H indicate the thick setae. Scale bars 150 μm in fig. A and 60 μm in figs B–F.

FIGURE 3. Eukoenenia mocororo sp. nov., holotype.A, trochanter-tibia of left palp; B, basitarsus 1-tarsus 2 of right palp. Scale bars 100 μm.

FIGURE 4. Eukoenenia mocororo sp. nov. A, tarsus 3 of right pedipalp (holotype); B, trochanter-tibia of right leg I (holotype); C, bsitarsus 1-tarsus 2 of right leg I (holotype); D, tarsus 3 of right leg 1 (paratype, ISLA13159). Scale bars 40 μm in fig. A and 100 μm in figs. B–D.

FIGURE 5. Eukoenenia mocororo sp. nov., holotype. A, basitarsus of left leg IV (scale bar 100 μm); B, opisthosoma, ventral view (scale bar 300 μm).

FIGURE 6. Eukoenenia mocororo sp. nov. A, male genitalia, holotype (scale bar 60 μm); B, female genitalia (paratype ISLA 101122); C, primordia of genital lobes, immature C (ISLA 13161); D, primordia of genital lobes, immature B (ISLA 13160). Scale bars 60 μm in fig. A and 40 μm in figs. B–D.

FIGURE 7. Eukoenenia mocororo sp. nov. A, tergite V (holotype); B, sternite VI (holotype); C, sternite IV (paratype, ISLA 101122); D, flagellar segments I–II (paratype, ISLA 101122); E, flagellar segments III–VIII (paratype, ISLA 101122); F, flagellar segments X–XIV (paratype ISLA, 101122). White arrows in figure C indicate a pair of small orifices between a1 setae. Scale bars 20 μm in figs A–B, 50 μm in fig. C, and 100 μm in figs D–F.