Bitabulata sagai, Goldschmidt, 2008

Goldschmidt, Tom, 2008, Taxonomical, ecological and zoogeographical studies on anisitsiellid water mites (Acari: Hydrachnidia: Anisitsiellidae Koenike, 1910) from Madagascar, Zootaxa 1954 (1), pp. 1-120 : 85-88

Bitabulata sagai sp. nov.

( Figs 197–210 , Table 10)

Type series: Holotype male, MD 100 a, Ankaratra (Antananarivo), Reserve Manjakatompo, Montagne Arirana , spring area exposition south-east (drainage Rivière Ambodimangavo), 2200 m asl, 13.5 °C, 1-9 µS/ cm, 05.10.2001, mounted; paratype, same locality and date, 0/1/0 mounted, 1/3/0 unmounted.

Habitat: Spring at 2200 m asl.

Distribution: Madagascar (Central mountains, Ankaratra).

Derivatio nominis: Sagai (Malagasy) — spear; referring to the anteriorly pointed first coxae of the species.

Diagnosis: Anterior and posterior dorsal plate with antero-lateral ridge; Dgl-2 on elongated platelet; ventral shield oval drop-shaped; caudal margin of Cx-IV oblique to anterior, genital field elongated, posteriorly surpassing genital bay; Vgl-2 and -4 fused with caudal margin of ventral shield; legs relatively slender; capitulum elongated; palp relatively slender (especially P4).

Description, male (n = 1): Idiosoma oval drop-shaped ( Fig. 197 ), purple-bluish; dorsal shield relatively broad (L/W 730/483), anterior plate triangular-rounded, caudal margin straight, laterally and anteriorly curved (L/W 268/425), bearing post-ocular setae; posterior plate (L/W 462/483) with slight antero-laterally extended corners bearing Dgl-4, Dgl-5 fused to postero-lateral margin; antero-medial area of plates slightly raised against antero-lateral margins ( Fig. 198 ); Dgl-2 on irregularly elongated platelet, soft integument lined; setae of Dgl-3 to -5 large, others mid-sized ( Fig. 198 ); lateral eyes oval, far separated from each other, free under integument, posterior eyes relatively large ( Fig. 198 ); venter nearly completely covered by ventral shield (L/ W 788/599); Cx-I anteriorly triangular, medially long, medial margin fused, lateral margin of Cx-II/III relatively straight, Cx-I/II anteriorly surpassing ventral shield; ventral shield extending dorso-laterally of Cx-III ( Fig. 197 ); latero-caudal and medio-caudal margin of Cx-I/II overlapping Cx-III; Cxgl-2 and -4 at anterior margin of Cx-III, setae at Cxgl-4 very tiny; medial margins of Cx-III fused; Cx-IV oblique rectangular, medial margin anteriorly convex, caudally straighter, forming tight genital bay, medio-caudal corner rounded, caudal margin of Cx-IV oblique to anterior, with small pointed projection centrally, insertion of leg-IV lateral to anterior end of genital field, lateral margin of Cx-IV not visible, curved ridge on Cx-IV from medial of insertion of leg-IV to lateral of Cx-III ( Fig. 197 ); genital field elongated-oval, laterally straight, anteriorly and posteriorly rounded, posteriorly clearly extended beyond caudal margin of Cx-IV; acetabula elongated-oval, touching each other (Ac1 and Ac3 remote from anterior and caudal end of genital flaps), setae on genital flaps very tiny, most caudal pair longer; small area of articular membrane anteriorly and lateral to genital field ( Fig. 197 ); genital skeleton compact (not clearly visible, squeezed in preparation) ( Fig. 199 ); setae of Vgl-1 directly posterior to caudal margin of Cx-IV, Vgl-3 half way between coxal field and latero-caudal margin of ventral shield; Vgl-2 and Vgl-4 fused with caudal margin; legs relatively slender, especially leg-IV bearing many heavy setae (mainly distally pinnate), claws on leg-I to -III with fine dorsal and strong ventral clawlet ( Fig. 200 ); leg-IV-6 with mid-sized, pinnate sub-terminal seta ( Fig. 201 ); capitulum elongated, especially ventrally, ventral margin nearly straight ( Fig. 202 ); chelicera slender, with flat dorsal hump ( Fig. 203 ); basal palp segments compact, P1 with one dorsal seta; P2 with one ventro-lateral seta and four dorsal setae; P3 with three dorsal and one lateral setae; P4 relatively slender, ventral margin with flat hump far proximally, distally tapering ( Fig. 204 ).

Female (n = 1): Deeper purple-brownish than male; platelets of Dgl-2 less elongated ( Fig. 206 ); ventral shield similar to male, anterior coxae more rounded ( Fig. 205 ); genital field larger ( Fig. 205 , Table 10); Vgl-3 closer to coxal field, directly posterior caudal margin of Cx-IV ( Fig. 205 ); legs ( Figs 207, 208 ) and gnathosoma ( Figs 209, 210 ) similar to male, ventral hump at P4 further distally ( Fig. 210 ).

Remarks: Bitabulata paoma is differentiated from the two other species of the genus by a compact capitulum, relatively compact palps, short legs and having the caudal margin of Cx-IV more transverse. Bitabulata sagai is characterised by the fusion of the Vgl-2 and -4 with the ventral shield (in both sexes), longer (slenderer) distal leg segments and P4, and furthermore (especially in the female) a longer genital field, than in the other species. Bitabulata kelycoxae is characterised by a relatively broad, pear-shaped genital field, an anteriorly broad ventral shield, relatively small Cx-I to -III, elongated capitulum and slender, distinctive dorsal plates. Therefore, even though these three species are based upon only six specimens, they are definitely three separate species.

Figures

FIGURES 197–204. Bitabulata sagai gen. et sp. nov., male holotype (MD 100a): 197, idiosoma, ventral view; 198, idiosoma, dorsal view; 199, genital skeleton, posterior view; 200, leg-II; 201, leg-IV-2 to -6; 202, capitulum with left palp (P5 missing), lateral view; 203, left chelicera, lateral view; 204, right palp, medial view. Scale bars = 100 µm.

FIGURES 205–210. Bitabulata sagai gen. et sp. nov., female paratype (MD 100a): 205, idiosoma, ventral view; 206, idiosoma, dorsal view; 207, leg-II-2 to -6; 208, leg-IV; 209, capitulum with left palp and chelicera, lateral view; 210, right palp, medial view. Scale bars = 100 µm.