Dorycranosus grenadaensis Ermilov, 2016

Ermilov, Sergey G., 2016, First record of the genus Dorycranosus (Acari, Oribatida, Liacaridae) from the Neotropical region, with description of a new species from Grenada, Ecologica Montenegrina 9, pp. 13-18 : 15-17

Dorycranosus grenadaensis Ermilov sp. nov.

( Figs 1–6 )

Diagnosis. Body size: 830–863 × 531–581. Body (except epimeral region) foveolate. Lamellar cusps with two distal teeth and concavity between them, inner teeth longer than outer teeth. With prodorsal tubercle between lamellar cusps. Rostral, lamellar and interlamellar setae long, setiform, slightly barbed, ro thinnest, in longest and thickest on prodorsum. Bothridial setae clavate, barbed. Setae p 1 longest on notogaster, erect, other notogastral setae thin, curved, all slightly barbed. Epimeral and anogenital setae thin, slightly barbed, 1a, 1c, 2a and 3a minute, 1b and 3b longest on epimeres, ad 1 and ad 2 erect, longer than ad 3. Six pairs of genital setae.

Description. Measurements. Body length: 863 (holotype, male), 830, 863 (two paratypes: males); notogaster width: 581 (holotype), 531, 564 (two paratypes).

Integument ( Figs 1–4 ). Body dark brown, covered with dense microgranules (their diameter less than 1). Dorsal and lateral sides, anogenital region and subcapitular mentum sparsely foveolate, foveoles (their diameter up to 4) slightly visible and not forming heavy ornamentation as in species of Xenillus Robineau- Desvoidy, 1839. Lateral parts of body (between notogaster and acetabula I–IV with dense tubercles (their diameter up to 6).

Prodorsum ( Figs 1 , 3 ). Rostrum with rectangular ledge and two lateral incisions. Lamellae (lam) slightly longer than half of prodorsum, separated medially. Lamellar cusps well developed, distally with two strong teeth and concavity between them, inner teeth clearly longer than outer teeth. Triangular prodorsal tubercle (tub) present between lamellar cusps. Translamella absent. Rostral (ro, 94–110), lamellar (le, 118– 131) and interlamellar (in, 266–287) setae setiform, slightly barbed, ro thinnest, in thickest. Bothridial setae (bs, 82–90) clavate, with longer stalks and shorter, elongate, barbed heads. Bothridia covered completely by anterior part of notogaster. Exobothridial setae and their alveoli absent. Tutoria (tu) ridge-like, similar to prodorsum in length, not reaching margins of rostrum.

Notogaster ( Figs 1–4 ). Anterior notogastral margin straight. Eleven pairs of notogastral setae developed, slightly barbed, p 1 longest (53–57), erect, other setae (20–28) thin, curved. All lyrifissures (except ia, not found) well visible, im located laterally to setae lm, ip laterally to h 1, ips anteriorly to p 3, ih anteromedially to ips. Opisthonotal gland openings (gla) located posteriorly to im and distanced from them.

Gnathosoma ( Figs 2 , 3 ). Subcapitulum longer than wide: 209–221 × 135–151. Subcapitular setae (h, 53–69; m, 53–61; a, 20–28) setiform, slightly barbed. Two pairs of adoral setae (or 1, or 2, 16) thickened, curved distally, barbed. Palps (127–139) with setation 0–2–1–3–8(+ω). Solenidia (12) thickened, blunt-ended, pressed to palptarsi surface. Chelicerae (209–221) with two setiform, barbed setae, cha (69–77) longer than chb (36–41). Trägårdh’s organ elongate triangular.

Epimeral and lateral podosomal regions ( Figs 2 , 3 ). Epimeral setal formula 3–1–3–3. Epimeral setae slightly barbed, 1a, 1c, 2a and 3a minute (6), erect, 1b, 3b (45–53) and 3c, 4a, 4b, 4c longer (24–32), thin. Pedotecta I (Pd I) represented by large scales. Discidia (dis) triangular. Circumpedal carinae (cp) distinct.

Anogenital region ( Figs 2 , 4 ). Six pairs of genital (g 1 – g 6, 24–28), one pair of aggenital (ag, 24–28), two pairs of anal (an 1, an 2, 32) and three pairs of adanal (ad 1, ad 2, 41–49; ad 3, 24) setae setiform, barbed. Adanal lyrifissures (iad) inverse apoanal. Setae ad 1 postanal, ad 2 and ad 3 lateral, ad 3 inserted posteriorly to iad.

Legs ( Figs 5, 6 ). Median claw slightly thicker than laterals, all serrate on dorsal sides. Dorso-paraxial porose areas (p.a.) on all femora and trochanters III, IV distinct. Formulas of leg setation and solenidia: I (1– 5[4]–3–4–20) [1–2–2], II (1–5[4]–3–4–16) [1–1–2], III (2–3–1–3–15) [1–1–0], IV (1–2–2–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1 . Famuli (ɛ) straight, slightly dilated and truncated distally. Solenidia ω 1 on tarsi I and ω 1, ω 2 on tarsi II blunt-ended, other solenidia pointed.

Material examined. Holotype (male) and two paratypes (males): Grenada, 12°5'44.48"N, 61°41'46.74"W, near Grand Etang, volcanic tuffs, forest with ferns, Selaginella and mosses near lake, wood decay, ferns and mosses, 24.I.1955, material was collected by Dr. P.W. Hummelinck (1907–2003) during his voyages in the Antilles, and sorted by Dr. M. Sellnick (1884–1971).

Type deposition. The holotype is deposited in the collection of the Netherlands Centre for Biodiversity Naturalis, Leiden, The Netherlands; two paratypes are deposited in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia.

Etymology. The specific name grenadaensis refers to Grenada, the island country in the Caribbean Sea, where the type material was collected.

Remarks. The new species is most similar to Dorycranosus shipitsyni ( Ermilov, Rybalov & Kemal, 2011) from Ethiopia (see Ermilov et al. 2011) in main morphological traits (body size large; lamellar cusps distally with two teeth and concavity between them, inner teeth longer than outer teeth; prodorsal tubercle present between lamellar cusps; p 1 longer than other notogastral setae). However, Dorycranosus grenadaensis sp. nov. differs from D. shipitsyni by the foveolate body surface (vs. body surface smooth), notogastral setae p 1 longer than adanal setae (vs. notogastral setae shorter than adanal setae), other notogastral setae well-developed, not shorter than diameter of bothridia (vs. minute, shorter than diameter of bothridia), adanal setae ad 1 and ad 2 longer than ad 3 (vs. all adanal setae similar in length).

Figures

Figures 1–2. Dorycranosus grenadaensis sp. nov.: 1 — dorsal view; 2 — ventral view (legs not illustrated except trochanters II and III). Scale bar 100 μm

Figures 3–4. Dorycranosus grenadaensis sp. nov.: 3 — anterior part of body, lateral view (legs except trochanter III not illustrated); 4 — posterior part of body, lateral view. Scale bar 100 μm.

Figures 5–6. Dorycranosus grenadaensis sp. nov.: 5 — leg I, without trochanter, right, antiaxial view; 6 — leg IV, left, antiaxial view. Scale bar 50 μm.