Hammerella (Hammerella) excisa, Ermilov, Sergey G. & Kalúz, Stanislav, 2013

Ermilov, Sergey G. & Kalúz, Stanislav, 2013, Three new species of Oppioidea (Acari: Oribatida) from India, Zootaxa 3670 (4), pp. 482-492 : 488-491

Hammerella (Hammerella) excisa sp. nov.

( Figs 25 –40)

Diagnosis. Body size 332–398 × 182–215. Rostrum with median indentation. Transcostula absent. Rostral, lamellar and interlamellar setae of medium size, similar in length. Sensilli with long stalk, weakly dilated elongate head, having several long branches. Notogastral setae c present. Genital and ano-adanal setae smooth.

Description. Measurements. Body length 365 (holotype), 332–398 (mean 365; five paratypes); notogaster width 199 (holotype), 182–215 (mean 205; five paratypes).

Integument ( Figs 25, 27 ). Body color light brown. Body surface smooth. Lateral side of prodorsum weakly microgranulate, latero-dorsal side with three to four of small, poorly visible muscle sigillae.

Prodorsum ( Figs 25, 27 –29). Rostrum with median indentation. Costula length less than half that of prodorsum. Transcostula absent. Rostral, lamellar and interlamellar setae similar in length (36–45), setiform, barbed. Exobothridial seta shorter (20–28), thin, indistinctly barbed. Sensillus (90–106) with long stalk, weakly dilated elongate head, having four to five long branches unilaterally (sometimes also one short branch additionally here). Interbothridial region with two pairs of unclear muscle sigillae. Postbothridial region with one pair of small tubercles.

Notogaster ( Figs 25, 27 ). Anterior margin straight, with one pair of distinct humeral tubercles opposing postbothridial tubercles. Notogastral seta c present, short (12), thin, smooth. The other nine pairs of setae longer, setiform, smooth or indistinctly barbed; la, lm, lp (49–61) longer than h 1– h 3, p 1– p 3 (28–41). Lyrifissures ia, im, ip, ih and ips distinct, thin, located typically for subgenus. Opisthonotal gland opening located posteriorly to lyrifissure im.

Gnathosoma (Figs 30–32). Subcapitulum longer than wide (94–102 × 65–69). Subcapitular setae setiform, barbed; h (28–36) longer than m (24–32) and a (16–20). Adoral setae and their alveoli absent. Palp (53–57) with setation 0–2–1–3–8(+ω). Solenidion thickened, dilated distally, inserted on anterior part of palptarsus and connected with distal seta. Chelicera (82–86) with two setiform, barbed setae; cha (28–32) longer than chb (28– 32). Trägårdh’s organ long, conical.

FIGURES 29–40. Hammerella (H.) excisa sp. nov., adult: 29—medio-distal part of sensillus; 30—subcapitulum, left half; 31—palptarsus; 32—anterior part of chelicera (Trägårdh’s organ not shown); 33—epimeral seta 4a; 34—genital plate, right; 35—anal seta an 2; 36—adanal seta ad 2; 37—tarsus and tibia (posterior part not shown) I, antiaxial view; 38—genu II, antiaxial view; 39—genu III, antiaxial view; 40—tarsus and tibia (posterior part not shown) IV, paraxial view. Scale bars (29, 31–36) 10 μm, (30) 20 μm, (37–40) 50 μm. The following figures to same scale: 36, 37; 37–40.

Epimeral and lateral podosomal regions ( Figs 26 , 33). Epimeral setae 1c (61–67) longer than 1b, 3b, 3c, 4a, 4b, 4c (32–36) and 1a, 2a, 3a (24–28). Pedotectum I convex. Discidium triangular, pointed.

Anogenital region ( Figs 26 , 34–36). Six pairs of genital (g 1– g 6, 12–16), two pairs of anal (20–28) and three pairs of adanal (36–45) setae setiform, smooth. One pair of aggenital setae (36–45) setiform, slightly barbed. Aggenital and adanal setae directed medially. Lyrifissure iad located in paraanal position.

Legs (Figs 37–40). Generally, the morphology is similar to other representatives of Hammerella ( Franklin & Woas 1992; Ermilov et al. 2012). Formulae of leg setation and solenidia: I (1–5–2–4–20) [1–2–2], II (1–5–2–4–16) [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 . Seta p setiform on tarsus I and thorn-like, very small on tarsi II–IV. Famulus straight, blunt-ended. Solenidia ω 1 on tarsus I, ω 1 and ω 2 on tarsus II thickened, blunt-ended; Solenidion σ on tibia III thickened, dilated in median part, blunt-ended; other solenidia setiform, thinner and longer.

Type deposition. The holotype is deposited in the collection of the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia; three paratypes are in the collection of the Siberian Zoological Museum, Novosibirsk, Russia; two paratypes are in the personal collection of the first author.

Etymology. The specific name “ excisa ” refers to the median indentation on rostrum.

Remarks. Hammerella (H.) excisa sp. nov. clearly differs from all species of the subgenus Hammerella (Hammerella) by the presence of median indentation on rostrum (versus median indentation absent) and notogastral setae c (versus setae c represented by alveoli).

Additional distinctive characters of Hammerella (H.) excisa sp. nov. with the other species of the subgenus Hammerella (Hammerella) can be found in an identification key below.

Figures

FIGURES 25 – 28. Hammerella (H.) excisa sp. nov., adult: 25 — dorsal view (legs not shown); 26 — ventral view (gnathosoma and legs not shown); 27 — lateral view of prodorsum (gnathosoma, epimeral setae and legs not shown) and anterior part of notogaster; 28 — rostrum and rostral seta. Scale bars (25 – 27) 100 μm, (28) 10 μm. The following figures to same scale: 25 – 27.