Ceratorchestes (Ceratorchestes) truncatus, Ermilov, 2024

Ermilov, Sergey G., 2024, New Ceratorchestes (Acari, Oribatida, Peloppiidae) from Venezuela, Zootaxa 5506 (4), pp. 555-566 : 561-563

Ceratorchestes (Ceratorchestes) truncatus sp. nov.

( Fig. 4 )

Material. Holotype (male) and four paratypes (three males and one female): northern Venezuela, Aragua State, Rancho Grande , 1450 m a.s.l., leaf litter, 26.II.1995 ( R. W. Brooks).

The holotype is deposited in the collection of the Canadian National Collection, Ottawa, Canada; four paratypes are deposited in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia. All specimens are preserved in 70% solution of ethanol with a drop of glycerol.

Diagnosis. Body length: 465–555. Rostrum tripartite, rostral protrusions similar in size, medial part triangular, simple, lateral parts toothlike distally. Lateral tooth of prodorsum strong. Lamellar cusp truncate; translamella present. Rostral and lamellar setae medium-sized, setiform, barbed; interlamellar seta long, slightly thickened, stiff, acuminate, barbed; bothridial seta long, setiform, shortly ciliated. All notogastral setae (except minute c) slightly thickened, stiff, acuminate, barbed; p 1, p 2 shorter than others. Epimeral setae 1b, 1c, 3b medium-sized, longer than others, slightly thickened, stiff, acuminate; 3a inserted in the same oblique row with setae of epimere IV. Adanal lyrifissure oblique to anal plate. Leg trochanter IV rounded dorsoanteriorly.

Description of adult. Measurements. Body length: 510 (holotype), 465–510 (male paratypes), 555 (female paratype); body width: 375 (holotype), 353–375 (male paratypes), 435 (female paratype).

Integument. Body color light brown. Surface densely microgranulate sculpturing (visible only under high magnification in dissected specimens; × 1000); lateral part of prodorsum between bothridium and acetabula I–III with larger granules (diameter up to 1).

Prodorsum ( Figs 4A, C ). Rostrum tripartite; all rostral protrusions similar in size, medial part triangular, slightly rounded apically, lateral parts toothlike distally. Lateral tooth of prodorsum tp strong. Lamella about 2/3 length of prodorsum; lamellar cusp truncate; translamella short, lineate; sublamella not observable. Rostral (41–45) and lamellar (56–75) setae setiform, barbed; rostral seta inserted medial to tutorial end and distanced from it; interlamellar seta (94–105) slightly thickened, stiff, acuminate, barbed; bothridial seta (123–139) setiform, shortly ciliated; exobothridial seta (45–49) setiform, thin, roughened.

Notogaster ( Figs 4A, C ). Anterior notogastral margin convex medially. Notogastral seta c (4) needleform; other notogastral setae (la, lm, lp, h 1 – h 3, p 3: 94–102; p 1, p 2: 56–67) slightly thickened, stiff, acuminate, barbed. Opisthonotal gland opening and all lyrifissures well observable.

Gnathosoma . Similar to C. (C.) tripartitus sp. nov. Subcapitulum size: 127–142 × 110–124; subcapitular setae a, m (26–30) setiform, roughened; h (30–37) slightly thicker, setiform, barbed; both adoral setae (9) setiform, thin, smooth. Palp length: 86–90; setation: 0-2-1-3-9 (+solenidion); postpalpal seta (7) spiniform, smooth. Chelicera length: 124–135; teeth of both digits small but well developed; setae (cha: 30; chb: 22) setiform, slightly barbed.

Epimeral and lateral podosomal regions ( Figs 4B, C ). Epimeral formula: 3-1-3-5; 1b, 1c, 3b (56–64) slightly thickened, stiff, acuminate, barbed; 3c, 4a, 4b, 4c, 4e (26–34) setiform, slightly barbed; 4d (34–45) setiform, barbed; 1a, 2a, 3a (15–19) setiform, thin, roughened; 3a noticeably distanced from 2a and inserted in the same oblique row with setae of epimere IV.

Anogenital region ( Figs 4B–D ). Anogenital formula: 6-1-2-3; genital setae (g 1: 19–26; g 2 – g 6: 15–19) setiform, roughened; aggenital (34–41), anal (26–37) setae and adanal setae ad 2, ad 3 (34–41) setiform, barbed; adanal seta ad 1 (41–52) slightly thickened, stiff, acuminate, barbed. Genital and anal plates in female noticeably larger than in males. Adanal lyrifissure close and slightly oblique to anal plate.

Legs. Similar to C. (C.) tripartitus sp. nov.

Remarks. The new species is similar to C. (C.) baloghi Mahunka, 1983 (see also Mahunka 1982) and C. (C.) cornutus Mahunka, 1982 in the presence of the truncate lamellar cusp, but differs from both by the morphology of the rostrum (tripartite versus pointed), in the presence (versus absence) of the translamella, longer and thicker epimeral seta 1c, and the location of epimeral seta 3a (inserted anteromedial to 4a versus posterolateral to 2a).

Etymology. The specific epithet truncatus refers to the morphology of the lamellar cusp (truncate).

Figures

FIGURE 4. Ceratorchestes (Ceratorchestes) truncatus sp. nov., adult, male (A–C) and female (D): A—dorsal view (legs omitted); B—ventral view (legs omitted); C—right lateral view (gnathosoma and legs omitted); D—anogenital region. Scale bar 100 μm.