Tritegeus luissantossubiasi, Ermilov, 2024

Ermilov, Sergey G., 2024, Taxonomic contribution to knowledge of the oribatid mite genus Tritegeus (Acari, Oribatida, Cepheusidae), Zootaxa 5556 (1), pp. 37-50 : 43-46

Tritegeus luissantossubiasi sp. nov.

( Figs 3 , 4 )

Type material. Holotype (female) and three paratypes (three females): India, 28°36'56''N, 95°53'21''E, Arunachal Pradesh State, Etalin , 700 m a.s.l., soil with litter in forest, 1–8.v.2012 (L. Dembický and O. Šauša). Two paratypes (two females): India, 28°19'32''N 95°57'31''E, Arunachal Pradesh State, Hunli, 1300 m a.s.l., soil with litter in forest, 26.v.–1.vi.2012 (L. Dembický and O. Šauša). Two paratypes (two females): India, 27°00'48''N 92°39'08''E, Assam State, Bhalukpong, 150 m a.s.l., soil with litter in forest, 1–8.v.2012 (L. Dembický and O. Šauša).

The holotype is deposited in the collection of the Senckenberg Museum of Natural History, Görlitz, Germany; seven paratypes are deposited in the collection of the University of Tyumen, Museum of Zoology, Tyumen, Russia . All specimens are preserved in 70% solution of ethanol with a drop of glycerol.

Diagnosis. Adult. Body size: 690–825. Medioposterior part of notogaster (between setae lp, h 2 h 3) with sparse, indistinct foveolae. Rostrum pointed. Lamellar cusps separated medially; translamella absent. Rostral seta setiform, with short, flexible tip, barbed; lamellar seta with thickened mediobasal part and flagellate distal part, with slight and sparse barbs; interlamellar seta thickened, acuminate, with slight and sparse barbs; in˃le˃ro; bothridial seta with shortly expanded head bearing numerous strong spines. Centrodorsal region of notogaster bordered by Ushaped thickening. Notogastral setae h 1 and p 1 comparatively short (p 1 ˃h 1), thickened, acuminate, heavily barbed; other setae long, thickened, acuminate, with slight and sparse barbs but with some strong barbs in distal part. All leg tarsi heterotridactylous; trochanters III and IV with long tooth dorsoanteriorly; seta pv’ on Ta I, II with ventral sparse spines; l” on Ti I, II and Ge I, II thickened; v’ on Ti I, II setiform, with ventral sparse spines.

Description of adult. Measurements. Body length: 780 (holotype), 690–825 (paratypes); notogastral width: 600 (holotype), 555–600 (paratypes).

Integument ( Figs 3A–D ). Body color dark brown. Body and legs partially covered by thick gel-like layer of cerotegument, including dense microtubercles. Surface with dense microtuberculate sculpturing, clusters of larger tubercles close and lateral to notogastral U-shaped thickening; lamella, humeral process, pedotecta I, II, podosomal region, discidium, lateral part of prodorsum, lateral part of epimere I partially foveate; medioposterior part of notogaster (between setae lp, h 2 h 3) with sparse, indistinct foveolae; lateral side of body between humeral process and acetabula II–IV with dense large tubercles; additionally, humeral process, podosomal region and dorsal part of pedotectum I partially rugose.

Prodorsum ( Figs 3A–C ). Rostrum pointed, observable in dorsal aspect. Rostral region with bulge. Outer tooth of lamellar cusp well developed. Translamella absent but medial parts of lamellae slightly protruding anteromedially, creating an illusion of the presence of a thin translamella. Tutorium with numerous teeth and small scales dorsally. Rostral seta (90–105) setiform, with short, flexible tip, barbed; lamellar seta (154–176) with thickened mediobasal part and flagellate distal part, with slight and sparse barbs; interlamellar seta (172–206) thickened, acuminate, with slight and sparse barbs; bothridial seta (90–112) with longer stalk and short expanded head bearing numerous strong spines; exobothridial seta represented by alveolus (may be broken).

Notogaster ( Figs 3A–D ). Centrodorsal region bordered by U-shaped thickening bearing dorsal notogastral setae. Setae h 1 (56–64) and p 1 (86–94) thickened, acuminate, heavily barbed; other setae (c, la, lm, lp, h 2, h 3: 146– 161; p 2, p 3: 101–124) thickened, acuminate, with slight and sparse barbs but with some strong barbs in distal part. Opisthonotal gland opening and all lyrifissures observable.

Gnathosoma ( Figs 4A–C ). Subcapitulum size: 154–161 × 123–135; subcapitular setae (a: 34–41; m: 13–15; h: 30–41) setiform, roughened; m thinnest; both adoral setae (15–19) setiform, smooth. Palp length: 94–97; postpalpal seta (11) spiniform, truncate, roughened. Chelicera length: 161–155; setae (cha: 37–41; chb: 28–30) setiform, barbed.

Epimeral and podosomal regions ( Figs 3B, C ). All epimeral setae (3c: 75; 4c: 56–71; 3b: 56–60; 1b, 4a, 4b: 41–52; 1c: 34–37; 1a, 2a, 3a: 15–19) setiform, roughened. Discidium large, elongate triangular, rounded distally.

Anogenital region ( Figs 3B–D ). Genital (g 1, g 2: 37–45; g 3: 30–37; others: 22–30), aggenital (30–37), anal (19– 26), and adanal (41–56) setae setiform, roughened. Adanal lyrifissure distinct, oblique.

Legs ( Figs 4D–G ). All tarsi with three claws; median claw thicker than lateral claws; all claws slightly barbed on dorsal side. Trochanters III and IV with long tooth dorsoanteriorly. Formulas of leg setation and solenidia: I (1- 5-3-4-20) [1-2-2], II (1-4-3-4-16) [1-1-2], III (2-3-2-3-15) [1-1-0], IV (1-2-3-3-12) [0-1-0]; homology of setae and solenidia indicated in Table 1; comparison of morphology of some setae between T. luissantossubiasi , T. tridactylus and T. mitratus presented in Table 2.

Remarks. Tritegeus luissantossubiasi is morphologically most similar to T. tridactylus in main traits: rostrum triangular; bothridial seta with developed head; cusps of the lamellae separated medially; centrodorsal region of the notogaster bordered by U-shaped thickening, without rugose sculpturing; dorsal notogastral setae long (distinctly longer than distance lm–lp), thickened, acuminate; tridactylous legs. However, the new species differs from the latter by shorter dorsal notogastral setae lp, h 2, h 3 (not longer than distance lp– h 2 versus longer), roughened, with sparse barbs in distal part (versus distinctly and entirely barbed); the length of the posterior notogastral setae (p 1 distinctly longer than h 1 versus slightly different in length), and the morphology of the seta v’ on the leg tibiae I, II (setiform, with ventral sparse spines versus thorn-like).

Etymology. This species is named after the late Prof. Dr. Luis. S. Subías, the famous taxonomist in oribatology.

Figures

FIGURE 3. Tritegeus luissantossubiasi sp. nov., adult: A—dorsal view (legs not illustrated); B—ventral view (legs not illustrated); C—lateral view (legs not illustrated); D—posterior view (part of left half not illustrated). Scale bar 200 μm.

FIGURE 4. Tritegeus luissantossubiasi sp. nov., adult: A—subcapitulum, ventral view; B—palp, right, antiaxial view; C— chelicera, right, antiaxial view; D—leg I, right, antiaxial view; E—leg II, right, antiaxial view; F—leg III, left, antiaxial view; G—leg IV, left, antiaxial view. Scale bars 50 μm (A, C–G), 20 μm (B).