Austrocarabodes (Austrocarabodes) madagascarensis, Ermilov & Starý, 2020

Ermilov, Sergey G. & Starý, Josef, 2020, Contribution to the knowledge of oribatid mites of the genus Austrocarabodes (Acari, Oribatida, Carabodidae) of Madagascar, Acarologia 60 (2), pp. 353-370 : 354-360

Austrocarabodes (Austrocarabodes) madagascarensis n. sp.

Zoobank: 7D4632FA-7DF3-411C-B137-ABE2DE2DE0DF

( Figures 1–4 )

Diagnosis — Body size: 381–448 × 215–265. Body with dense cerotegumental microridges. Notogaster sparsely foveolate, specific rows and congestions of foveolae also presented on prodorsum and in anogenital region. Translamella absent. Tutoria with tip curved medially. Rostral setae phylliform, dilated mediodistally, erect, lamellar setae narrowly phylliform, with spines and barbs, interlamellar setae narrowly phylliform, barbed; all setae comparatively long, barbed, in longest. Bothridial setae unilaterally dilated and spinose. Notogastral setae comparatively long (posterior setae shorter), narrowly phylliform, with short attenuate tips, barbed. Epimeral setae 1a, 1c, 2a and 3a minute, others longer, setiform, slightly barbed. Genital, aggenital and adanal setae setiform, slightly barbed. Anal setae short, setiform, erect, roughened. Lateral phylliform seta l” presented only on genua I, II.

Description — Measurements – Species of medium size. Body length: 448 (holotype: female), 381–448 (15 paratypes, all females); notogaster width: 265 (holotype), 215–265 (15 paratypes). Body ratio (length/width): 1.6–1.8.

Integument ( Figs 1 a-c, 2a-d, 3a, 3c, 3d, 4a-d) – Body color brown to dark brown. Body covered by thick layer of gel-like cerotegument and cerotegumental microridges and some microgranules. Body surface partially microtuberculate. In addition, notogaster sparsely foveolate, foveolae (their diameter up to 8) also partially presented on prodorsum (in basal part and as one pair of longitudinal rows in inner parts of lamellae), on lateral sides of prodorsum (between lamellae and tutoria and on tutoria), in anterolateral parts of ventral plate (pedotecta I and regions close to subcapitular mentum), in anogenital region (posterior and lateral to genital aperture, anterior and lateral to anal aperture, and as one row close to circumventral ridge), and on antiaxial sides of all leg femora and of trochanters III, IV. Epimeral region with some muscle sigillae.

Prodorsum ( Figs 1 a-c, 3a, 3c, 3d, 4a, 4c, 4d, 4g) – Rostrum broadly rounded. Lamellae long (slightly shorter than prodorsum), with distal triangular projection. Translamella not observed. Tutoria long, ridge-like, with tip clearly curved medially. With elongate depression (separated by transverse ridge) between lamellae and tutoria, and one depression ventrally to tutoria. Rostral setae (32–36) phylliform, dilated mediodistally, erect, barbed, inserted on tubercles. Lamellar setae (36–41) narrowly phylliform, with strong spines and small barbs, directed anteromedial. Interlamellar setae (65–77) narrowly phylliform, barbed, directed lateral. Bothridial setae (32–41) with elongate, unilaterally dilated and heavily spinose heads (sometimes setae appear clavate in dorsal view). Bothridia slightly interrupted ventrally, with inner tooth. Exobothridial setae vestigial.

Notogaster ( Figs 1a, 1c , 3a, 3c , 4a, 4b, 4d, 4h ) – Anterior notogastral margin slightly convex medially. Humeral processes poorly developed. Fourteen pairs of notogastral setae (p 1 – p 3, h 3, 28–30; others 49–61) narrowly phylliform, with short attenuate tips, barbed. Lyrifissures and opisthonotal gland openings distinct.

Gnathosoma ( Figs 2 e-g, 4f, 4g) – Subcapitulum longer than wide (90–98 × 73–77). Subcapitular setae (12) setiform, roughened. Postpalpal setae (8) bacilliform, slightly barbed mediodistally. Palps (49–53) with setation 0–2–1–3–9(+ω). Solenidion of palptarsi long, bacilliform. Chelicerae (98–106) with two setiform, barbed setae cha (, 36; chb, 12). Trägårdh’s organ of chelicerae elongate triangular.

Lateral podosomal and epimeral regions ( Figs 1b, 1 с, 3b, 3c, 4g) – Pedotecta II trapezoid in ventral view. Discidia triangular, rounded distally. With typical epimeral setation 3–1–3–3. Epimeral setae 1a, 1c, 2a and 3a short (4–6), setiform, smooth, 1b, 3b, 3c, 4a, 4b and 4b (28–32) setiform, slightly barbed.

Anogenital region ( Figs 1b, 1c , 3b, 3c , 4b, 4f ) – With one pair of short, longitudinal ridges lateral to genital aperture and posterior to epimere IV. Four pairs of genital (14–16), one pair of aggenital (14–18) and three pairs of adanal (14–18) setae setiform, slightly barbed. Two pairs of anal setae (6–8) setiform, erect, roughened. Adanal lyrifissures visible, removed from anal aperture and located anterolateral to adanal setae ad 3. Circumventral ridge developed.

Legs ( Figs 2 a-d, 3b, 3c) – Claw of each leg strong, sparsely barbed dorsally and with tooth ventrobasally. One porose area on all femora distinct, porose areas on trochanters III, IV not observed. Formulas of leg setation and solenidia: I (1–4–3–4–16) [1–2–2], II (1–4–3–3–15) [1–1–2], III (2–3–1–2–15) [1–1–0], IV (1–2–2–2–11) [0–1–0]; homology of setae and solenidia indicated in Table 1. Famulus of tarsi I short, erect, blunt-ended. Solenidion φ 1 on tibiae I very long, setiform; other solenidia shorter, thickened, blunt-ended to bacilliform. Seta l” on femora I, II and l’ on femora III and genua III thickened, seta l” on genua I, II phylliform.

Material examined — Holotype (female) and 15 paratypes (15 females): North Madagascar, Montagne d’Ambre National Park, circuit Ampijoroana, evergreen rain forest, 12°31’28’‘S, 49°09’52”E, 950 m a.s.l., sifting of leaf litter sample under big unidentified tree, Winkler apparatus extraction, 13.I.2014 ( R. Ravebolun and L. Rabotenoson).

Type deposition — The holotype and three paratypes are deposited in the collection of the Senckenberg Institute, Görlitz, Germany. Twelve paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. All specimens are preserved in ethanol with a drop of glycerol.

Etymology — The name of the new species, madagascarensis , refers to the place of origin, Madagascar.

Remarks — In the presence of dilated mediodistally rostral setae and long, narrowly phylliform (with short attenuate tips) notogastral setae, Austrocarabodes madagascarensis n. sp. is morphologically most similar to Austrocarabodes similis Mahunka, 1978 from Mauritius and A. spathulatus Mahunka, 1978 from Réunion, but differs from both by the presence of foveolae on the body surface (versus foveolae completely absent).

Figures

Figure 1 Austrocarabodes madagascarensisn. sp., adult: a – dorsal view; b – ventral view (legs omitted); c – lateral view (gnathosoma and legs omitted). Scale bar 100 μm.

Figure 2 Austrocarabodes madagascarensisn. sp., adult: a – leg I, left, paraxial view; b – femur, genu and tibia of leg II, right, antiaxial view; c – leg III, without tarsus, left, antiaxial view; d – leg IV, left, antiaxial view; e – subcapitulum, ventral view; f – palp, right, antiaxial view; g – chelicera, right, antiaxial view. Scale bar 20 μm (a–e; g), scale bar 10 μm (f).

Figure 3 Austrocarabodes madagascarensis n. sp., adult, SEM micrographs: a – dorsal view; b – ventral view; c – lateral view; d – rostral and lamellar setae and distal part of lamella, dorsoanterior view. Scale bar 100 μm (a–c), scale bar 20 μm (d).

Figure 4 Austrocarabodes madagascarensisn. sp., adult, SEM micrographs: a – anterior view; b – posterior view; c – rostral seta; d – bothridial seta, humeral process, some notogastral setae and part of sejugal region, dorsal view; e – part of anoadanal region; f – gnathosoma, ventral view; g – gnathosoma and anterolateral part of prodorsum, lateral view; h – bothridial seta, bothridium, humeral process, some notogastral setae and sejugal region, lateral view. Scale bar 100 μm (a), scale bar 50 μm (b), scale bar 20 μm (c–h).