Vahatra ambohitra Leever & Daniels & Soma & Cumberlidge 2022, comb. nov.
Creators: name: Leever, Ellen M.
name: Daniels, Savel R.
name: Soma, Julia B.
name: Cumberlidge, Neil
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamonautidae
Vahatra
Vahatra ambohitra

description: Vahatra ambohitra (Cumberlidge and Meyer 2009) comb. nov.
(Figures 1 (a,c,e), 2(a,c,e), 3(a), 4(a,b,e,f), 5(a,b,c), 6; Tables 1–4)
Foza ambohitra Cumberlidge and Meyer, 2009: 79–84, figs 1–3, tab. 1) (partim, not NMU PN 17– 21.3.2003).
Material examined
Type material. Holotype: Madagascar: adult ♂ (CW 39.5, CL 32.4, CH 16.3, FW 8.7 mm), Antsiranana Province, Diana Region, forest close to Ambohitra (formerly Joffreville) (12.4500°S, 49.133333°E), 421 m ASL, coll. R. Roy, May 2005 (MNHN B 30154) (GenBank MT749728).
Paratypes: Madagascar: adult ♀ (CW 37.8, CL 29.6, CH 15.5, FW 8.0 mm), subadult ♀ (CW 30.0, CL 23.6, CH 12.7, FW 6.6 mm), Antsiranana Province, Diana Region, Analamerana Special Reserve, Ankavanana Forest, 15.8 km south-east of Anivorano-Nord (12.4500°S, 49.133333°E), from partially disturbed mixed dry deciduous and humid forest, in early morning, 200 m ASL, coll. M. Raheriarisena, S.M. Goodman, 23 January 2004 (FMNH 11045); adult ♂ (CW 38.4, CL 28.8, CH 15.0, FW 8.3 mm), adult ♀ (CW 35.0, CL 28.0, CH 14.3, FW 8.1 mm), same data as FMNH 11045, but found during night at edge of small stream at forest edge, coll. H. Rakotondravony, 23 January 2004 (FMNH 11046) (GenBank MT749727); adult ♂ (CW 37.1, CL 29.2, CH 16.8, FW 8.1 mm), same data as FMNH 11045, but found in late afternoon, coll. S.M. Goodman, 25 January 2004 (FMNH 11050); adult ♀ (CW 38.0, CL 28.7, CH 15.7, FW 8.5 mm), adult ♂ (CW 33.2, CL 26.2, CH 14.5, FW 7.5 mm), same data as FMNH 11050, coll. M. Raheriarisena, S. M. Goodman (FMNH 11051); adult ♀ (CW 39.1, CL 30.7, CH 17.1, FW 8.7 mm), same data as FMNH 11045, but found at forest edge during night, coll. J. Ravino, 25 January 2004 (FMNH 11052); adult ♀ (CW 41.4, CL 31.9, CH 17.4, FW 8.7 mm), same data as FMNH 11045, but found on ground during day, coll. M. Raheriarisena, S.M. Goodman, 26 January 2004 (FMNH 11054); adult ♀ (CW 43.1, CL 34.2, CH 18.3, FW 9.9 mm), same data as FMNH 11045, but found in late afternoon, coll. S. M. Goodman, M. Raheriarisena, 28 January 2004 (FMNH 11056); juv. ♂ (CW 22.8, CL 17.6, CH 9.4, FW 4.7 mm), Antsiranana Province, Analamerana Special Reserve, Ankavanana Forest, 8.6 km south-east of Menagisy, Foret d’Analabe, along Bobakindro River (12.4500° S, 49.133333°E), from disturbed dry deciduous forest, in early morning, 40 m ASL, coll. S.M. Goodman, 17 January 2004 (FMNH 11060).
Other material. Madagascar: 2 adult ♂♂ (CW 50, Cl 31.6 mm; CW 43, CL 30 mm), Antsiranana Province, Diana region, Ankarana Special Reserve (12.9200°S, 49.1400°E), coll. F. Glaw, M. Franzen, J. Köhler and N. d’Cruze, 13 February 2008 (ZSM A20145001, ZSM A20145002).
Diagnosis
As for genus.
Redescription
Based on holotype, adult ♂. Carapace outline transversely oval, extremely high (CH /CW 0.42); front narrow (FW/CW = 0.22), deflexed; entire carapace surface generally smooth. Epibranchial tooth small, acute, close to exorbital tooth, positioned in line with postorbital margin; lateral margin evenly curved outward, smooth, continuous with posterolateral margin; postfrontal crest faint, incomplete, not traversing entire carapace, epigastric crests faint, in line with postorbital margin, postorbital crests faint, ending before meeting exorbital tooth; cardiac, urogastric sulci faint, semicircular sulcus deep, cervical sulcus broad, faint, long, not meeting postorbital crest (Figure 1 (a)). Suborbital, subhepatic regions of branchiostegite smooth, pterygostomial region smooth except for small field of granules at junction of longitudinal, vertical sulci; vertical sulcus on branchiostegite curved, granular, running downward from base of epibranchial tooth to epimeral sulcus (Figure 1 (c)). Epistomial tooth triangular, deflexed, edges smooth (Figure 1 (c)). Mandibular palp terminal article bilobed, anterior lobe on terminal article conspicuous, medium-sized (MPAL/MPTA = 0.4) (Figure 2 (a,c); Table 2). Exopod of third maxilliped reaching to lower half of merus, exopod with short flagellum (less than half merus length), ischium with deep vertical sulcus, beginning distally close to medial margin, angled diagonally downward (Figure 2 (e)). Sternal suture S1/2 short, faint; S2/3 completely traversing sternum; S3/ 4 broad, U-shaped, deepest at edges, not meeting anterior margin of sternopleonal cavity; anterior sternopleonal cavity lacking setae; S4/5 meeting pleon at telson/PL6 suture; S6/7 meeting midpoint of lateral margin of PL6; episternal sulci S4/E4, S5/E5, S6/E6, S7/E7 absent, smooth (Figure 1 (e)). Right chela largest, proximal half of cutting edge of fixed finger (pollex of propodus) with four large molars, small teeth distally; cutting edge of movable finger (dactylus) with two large teeth proximally, one large tooth midway (Figure 4 (a)); left chela subequal to right chela, dentition same as right chela (Figure 4 (b)); lower margin of propodus of both chela slightly indented medially (Figure 4 (a,b)). Distal tooth on inner margin of cheliped carpus large, pointed; proximal tooth significantly smaller, acute, followed by small granules (Figure 4 (f)). Inferior margins of cheliped merus both lined with small, rounded teeth, distal tooth largest; superior side of cheliped merus roughened by granules, short striae; cheliped ischium margins smooth, rounded (Figure 4 (e)). Ambulatory legs P2–5 short (ΣP2–5/CW = 5.7) (Figure 3 (a); Table 3). Male pleon plus telson triangular, tapered distally, widest at PL3, narrowest at telson; PL6 relatively broad, with convex lateral margins; telson outline with straight lateral margins, apex rounded (Figure 1 (e)). Sulcus between G1 TA, G1 SA faint on ventral side, distinct on dorsal side; G1 TA medium length (G1 TA/G1 SA = 0.3), dorsal side glabrous, slim, broadest proximally, distal half curving upward, tip broad; G1 SA with distinct raised rounded shoulder on external margin near G1 TA-SA junction (Figure 5 (a,b)). Broad, trapezoid membrane (DM) on dorsal side of G1 TA-SA junction; DM superior margin diagonal, inferior margin J-shaped, lateral margin broad, mesial margin narrow (Figure 5 (b)). G2 TA long (G2 TA/SA = 0.6), flagellum-like with distinct distal curve (Figure 5 (c)).
Size
Medium-sized species, largest known specimen CW 50 mm, pubertal moult between CWs 37 and 43 mm.
Colour
Unknown in life. Preserved specimens are uniformly pale brown.
Distribution
Vahatra ambohitra (Cumberlidge and Meyer, 2009) comb. nov. has a distributional range that includes Ambohitra, the Ankarana Special Reserve and the Analamerana Special Reserve, all in the Diana Region of Antsiranana Province in northern Madagascar (Figure 6). This distributional range no longer includes Akirindro Mountain in northern Toamasina Province because the specimen from that locality (NMU PN 17– 21.3.2003) is not now recognised as belonging to this species (see remarks section below).
Type locality
Madagascar; Antsiranana Province, Diana Region, forest close to Ambohitra (formerly Joffreville) (12.450000°S, 49.133333°E), 421 m ASL.
Habitat
Vahatra ambohitra (Cumberlidge and Meyer, 2009) comb. nov. dwells on land, near small streams in partially disturbed mixed dry deciduous and humid forests of northern Madagascar near the village of Ambohitra. The Ankarana Special Reserve and the Analamerana Special Reserve are both part of the Ankarana Highlands with dry deciduous and riverine forest that includes limestone formations (tsingy) with numerous caves and canyons.
Remarks
The species was formerly assigned to Foza based on morphological characters but is removed from that genus based on molecular evidence and further morphological analysis. The paratypes from the Analamerana Special Reserve (FMNH 11045, 11046, 11050, 11051, 11052, 11054, 11056 and 11060) are retained in this species because one of these (FMNH 11046) was sequenced (GenBank MT749727) and is positioned next to the sequence (GenBank MT749728) for the holotype of V. ambohitra (Cumberlidge and Meyer, 2009) comb. nov. on the phylogenetic tree in Cumberlidge et al. (2020, fig. 1).
Vahatra ambohitra can be distinguished from F. raimundi mainly by the G1 TA which is glabrous on the dorsal side in V. ambohitra (Figure 5 (b)), vs a G1 TA that is heavily setose on the dorsal side in F. raimundi (Figure 7 (h)); by a lack of setae on the superior part of the pterygostomial region and on the anterior subpleonal cavity in V. ambohitra (Figure 1 (c); Cumberlidge and Meyer (2009, fig. 2B,C), vs both these regions distinctly setose in F. raimundi (Figure 7 (b,c); Reed and Cumberlidge (2006, fig. 1A, I); and by the movable and fixed fingers of the major chela in V. ambohitra that have three and four large molars, respectively (Figure 4 (a)), vs a movable finger with no large molar teeth, and a fixed finger with only one large molar on the pollex of the major chela in F. raimundi (Reed and Cumberlidge, 2006, fig. 1e).
Conservation status
The conservation status of V. ambohitra (Cumberlidge and Meyer, 2009) comb. nov. is assessed as Least Concern (LC) on the International Union for Conservation of Nature Red List (Cumberlidge 2016; Cumberlidge et al. 2017), but this now needs to be reassessed because the present taxonomic revision significantly reduces the extent of occurrence of this species from 5874 km 2 (five locations) to 935 km 2 (four locations) (Figure 6).
description: Published as part of Leever, Ellen M., Daniels, Savel R., Soma, Julia B. & Cumberlidge, Neil, 2022, Two new genera and a new species of freshwater crabs from northern Madagascar: Vahatra gen. nov. for Foza ambohitra Cumberlidge and Meyer, 2009, and Toamasina gen. nov. for Toamasina clarki sp. nov. (Brachyura: Potamoidea: Deckeniidae), pp. 241-263 in Journal of Natural History 56 (1 - 4) on pages 251-254, DOI: 10.1080/00222933.2022.2049389, http://zenodo.org/record/6758291