Rhynchoribates (Tectorhynchoribates) jurobales, Miko, Ladislav, 2016

Miko, Ladislav, 2016, Oribatid mites (Acarina, Oribatida) from French Guyana: review of the genus Rhynchoribates and description of three new species, Zootaxa 4061 (2), pp. 131-145 : 138-141

Rhynchoribates (Tectorhynchoribates) jurobales n. sp.

( Figs 3–4 )

Material. Holotype and one paratype (sex not determined), French Guyana, Montagne de Kaw, near Auberge Camp Caiman, close to reserve Coq du Roche (4°34´23´´N, 52°11´58´´W), 150 m above sea level (sample Nr. LM- 2012-008). Litter, dead leaves and rotting wood on the soil surface in tropical rainforest. Collected by author, 10.III.2012.

The holotype is deposited in arachnological collection of National Museum of Prague, Czech Republic, paratype in the collection of the author.

Diagnosis. Medium sized Rhynchoribates . Diagnosis as for subgenus Tectorhynchoribates, with following additions. Rostrum sharply attenuated, pointed. Prodorsum with sclerotised ridges and large granules of cerotegument. Pedotectum I reaching in lateral view barely beyond anterior edge of acetabulum I, discidium also relatively small, so its tip usually not visible in dorsal view. Interlamellar setae very long, much longer than other prodorsal setae. Notogastral setae setiform, with attenuated tips, long, lm, lp and h1 longest, h1 and h2 inserted on sclerotised tubercles. Ventral plate with cuticular thickenings in epimeral area. Adanal setae ad1 significantly longer than other ventral setae, aggenital setae developed as flattened blades pointed distally. With porose areas in epimeral area and in lateral parts of body.

Description. Body length of holotype 696 (paratype 679), ventral body length 648 (636), maximum body width 415 (412, between tips of discidia). Prodorsum length 348 (333), maximum prodorsum width 285 (282).

Integument. Colour brown to reddish brown. Body covered with layer of fine, granular cerotegument. Central part of prodorsum at rostrum base, lateral parts of prodorsum, pedotecta I and discidia covered by large, dark cerotegument tubercles, with diameter below 10 ( Figs 3 A, 4A).

Prodorsum. ( Figs 3 A, 4A). Rostrum elongate, strongly attenuating, sharp at tip, with entire edges without teeth. Rostral furrows distinct, diverging posteriad. Surface of prodorsum with several transversal and oblique ridges in central part and at base of rostrum. Lamellar knob developed, blunt anteriorly, its base surrounded by ridges. Interbothridial region with transversal ridges, not connected medially, with thickenings bearing setae in. Bothridia with well sclerotised walls, opening laterad, openings almost invisible in dorsal view. Setae ro long (128–135), setiform, distally pointed, inserted at midlength between rostral tip and acetabulae I. Setae in very long (207–235), setiform, with flagelliform tips. Setae le (86–92) setiform, bent ventrad, inserted below projection of lamellar knob, at its base, near each other (le–le = ro–ro). Setae ex shortest of prodorsal setae (37–38), hardly visible in dorsal view. Sensillus form as typical for majority of Rhynchoribates species, with short straight proximal part and strongly curved distal part, very slightly broadened in middle, with pointed tip, very long (234–254). Discidia relatively small, tips of discidia hardly visible from dorsal view.

Notogaster. ( Figs 3 A, 4A). Notogaster circular, with distinct but flat humeral tubercles, each projecting posteriad by rather long carina reaching insertion of seta c2 (visible in lateral view). Setae h1 and h2 inserted on sclerotised flat tubercles or short ridges. Small, round porose area present at the lateral outline of notogaster, visible in lateral view, covered by small cuticular tectum (p. a., Fig. 4 A). Similar but larger area present laterally just below notogastral edge (above acetabulum IV when seen laterally). Notogastral setae long to very long, setiform with attenuated flagelliform tips, which brake easily. Seta h1 longest (up to 390), setae of l -row and h2 over 200, c2, h3 and p1 155–175, seta p3 shortest (below 70). Lyrifissures and glandular openings at usual places.

Gnathosoma elongated, narrow in distal part, with characters as usual in Rhynchoribates . Mentotectum relatively narrow. Palp setation 2–1–3–8(1).

Epimeral region. ( Figs 3 B, 4A, B). Tectum of podocephalic fossa (tpf, Figs 3 B, 4B) posterolaterad with short and acute tip. Another tectum (tcpl, Fig. 4 B) developed behind, covering lateral parts of epimere I, its edge appears as distinct oblique line connecting posterior part of infracapitulum and area below acetabulum II (black arrows on tcpl), posterior end of this tectum with angular projection. Distinct cuticular thickenings present paraxially on apodemes II and III, setae 1a inserted on blunt tubercular apophyses. Apodeme II partly covered by narrow tectum (tcap, Fig. 4 B) Cuticular thickening bridges ventrosejugal furrow medially (ventrosejugal bridge, vb, Figs 3 B, 4B). Pair of distinctly framed, round porose areas present behind this thickening. Epimeres IV laterally with quite long, longitudinal circumpedal ridges (cpl, Fig 3 B) separating discidial area and bearing setae 4e. Epimeral setal formula 3–1–3–5; setae 1c inserted on pedotectum I, setae 4a–4d inserted near each other creating characteristic group ( Fig. 4 B). All epimeral setae of comparable length (40–50, seta 1a up to 58) simple, setiform.

Anogenital region. ( Fig. 3 B). Genital opening smaller than anal opening, distance between them shorter than length of genital opening. Genital plates oval, broadest in anterior third. Anal plates semi-circular, with rugged anterior angles. 7 pairs of genital setae present, all smooth, fine, setiform ( Figs 3 B, 4A), medium long (around 40). Setae ag ( Figs 3 B, 4A) flattened, elongated and pointed (lancetiform). Two pairs of very short (around 8), fine, setiform anal setae inserted in anterior half of plates. Adanal setae unequally developed, ad2 and ad3 fine, setiform and short (25–28), seta ad1 much longer (86–90), setiform, with curved and attenuated distal part. Lyrifissures iad inverse apoanal, or almost perpendicular, positioned at a distance from anal opening.

Legs. ( Fig. 4 C–D). Legs monodactyle. Setal formula (famulus included, solenidia in parentheses) as follows: leg I 1–5 –2(1)–4(2)–20(2), leg II 1–5 –1(1)–4(1)–17, leg III 2–3 –1(1)–3(1)–15, leg IV 1–2 –2–3(1)–12 (for homology of setae see Table 1 ). Solenidia φ1 and φ2 of tibia I ceratiform, blunt, slightly curved and medium long, other solenidia similarly shaped but shorter. Leg setae mostly simple setiform and smooth, relatively long. Lateral and dorsal setae of femora and tibiae stronger, less attenuated distally and more blunt than others. Famulus short, simple, setiform. Proral setae of tarsus I simple, setiform, on leg IV modified, short, bacilliform ( Fig. 4 E).

Remarks. The new species differs from all known Rhynchoribates species by special development of its epimeral area, with large tectum on epimere I, which is seen as the main subgeneric character. Beyond that, the presence of attenuated rostrum without denticulation, with pattern of sclerotised ridges on the prodorsum and long setae in, could only be found in a few other species of the nominal subgenus. Recently described R.(s. str.) longisetosus Ermilov, Sandmann, Marian, Maraun, 2014 is rather close, and R. (s. str.) edentatus Balogh & Mahunka, 1969 is somewhat similar as well. Only R. (s. str.) longisetosus has quite long notogastral setae comparable to those of the new species, however, in the new species there are much larger differences in the length of notogastral setae, and the longest setae (h1) reach almost the whole length of the notogaster. Further differences could be found in development of rostral setae (reclined in R. (s. str.) longisetosus , bent but pointing anteriad and inserted at a distance from rostral tip in R. (T.) jurobales n. sp.), length of lamellar and exobothridial setae (le longer than ro in R. (s. str.) longisetosus , ex much longer than in R. (T.) jurobales n. sp.) and in ventral characters (adanal setae similarly shaped, posterior genital setae much longer, aggenital setae not modified, lyrifissures iad paraanal, close to anal opening in R. (s. str.) longisetosus ). On the other hand, there are characters developed similarly in both species—e.g. presence of sclerotised structures in epimeral region or presence of oval/rounded area (area porosa?) behind ventrosejugal groove. Similar characters were observed also in other species, so apparently they may appear broadly throughout the family Rhynchoribatidae . R. (s. str.) edentatus can be easily distinguished form the new species among other characters by much shorter notogastral setae, in with clavate tip, much longer setae ex and differently shaped and positioned rostral setae.

Derivatio nominis. The species is dedicated to the three colleagues, entomologists participating in French Guyana expedition–Jura Szányi, Robert Lízler and Aleš Dolný. The name of species was created as a combination of their given names (Jura, Robert and Aleš = Ju–Rob–Ales).

Figures

FIGURE 3. Rhynchoribates (Tectorhynchoribates) jurobales n. sp., holotype. A—dorsal view; B—ventral view (gnathosoma not depicted). Acronyms: cpl—circumpedal ridge, gla—opistosomal glands, tpf—tectum of podocephalic fossa. Scale bar: 200 µm.

FIGURE 4. Rhynchoribates (Tectorhynchoribates) jurobales n. sp. A—lateral view; B—detail of epimeral area; C—leg I; Dleg IV; E—detail of distal part of tarsus IV with bacilliform proral setae. Acronyms: p. a. — porose area, tcap — tectum above apodeme 2, tcpl — pleural tectum, tpf — tectum of podocephalic fossa, vb — ventral bridge over sejugal area. Scale bars: 200 µm (A), 100 µm (C – D).