Vichai cyanapelou gen. et sp. nov. (Crustacea: Deckeniidae: Hydrothelphusinae), a new genus and new species of freshwater crab from northern Madagascar Author Cumberlidge, Neil Author Daniels, Savel R. Author Soma, Julia B. Author Leever, Ellen M. text Journal of Natural History 2023 2023-04-20 57 5 - 8 463 474 http://dx.doi.org/10.1080/00222933.2023.2192431 journal article 10.1080/00222933.2023.2192431 64f4ca9e-4556-45ac-8a57-00fc3a16e837 1464-5262 7859817 Vichai gen. nov. ( Figures 1 (a,b), 2(a–i), 3(a–d); Table 1 ) Nomenclatural statement A life science identifier (LSID) number was obtained for the new genus: urn:lsid:zoobank. org:pub: 46218584-43FE-4C05-9537-FFC81EACCFDB Synonymy ′New genus E̍, Cumberlidge et al. (2020) : fig. 1. Type species Vichai cyanalepou sp. nov. , by present designation, gender masculine. Diagnosis Carapace moderate height (CH/FW 1.0); front broad (CW/FW = 3.1), deflexed; surface with faint carinae in anterolateral and posterlateral regions, otherwise smooth; anterolateral margin between exorbital tooth, epibranchial tooth concave, granulated,lacking intermediate tooth; epibranchial tooth reduced to small granule, close to exorbital tooth, positioned in line with postorbital margin; lateral margin strongly convex, lined with granules, posterior end curving inward, not continuous with posterolateral margin; postfrontal crest faint, incomplete, not traversing entire carapace, epigastric crests faint, in advanced position, in line with postorbital margin, postorbital crests faint, ending before meeting epibranchial teeth; semicircular, cervical sulci deep, cervical sulcus ending before meeting postorbital crest ( Figure 1 (a)). Suborbital, subhepatic regions of branchiostegite with faint granules, pterygostomial region smooth except for granules along epimeral (longitudinal) sulcus; vertical sulcus on branchiostegite curved, granular, running downward from base of epibranchial tooth to epimeral sulcus ( Figure 1 (b), 2(a)). Epistomial tooth triangular, deflexed, edges with faint granules, epistomial margins smooth ( Figure 2 (a)); anterior lobe on terminal article of mandibular palp small (MPAL/MPTA = 0.4) ( Figure 2 (i)). Ambulatory legs (P2–5) stout, not elongated (P2–5/CW = 5.4) ( Figure 1 (a); Table 1 ); cheliped ischium margins smooth, rounded ( Figure 2 (d)); third maxilliped exopod with long flagellum (~0.5× merus length) ( Figure 2 (g,h)). G1TA medium length (G1TA/G1SA = 0.3), slim, basal two-thirds directed outward, distal third curving upward, tapering to blunt open tip; G1TA ventral side with faint sulcus between G1TA-G1SA junction ( Figure 3 (a)); G1TA dorsal side with broad, trapezoid dorsal membrane (DM) at G1TA-G1SA junction; DM superior margin arrowhead-shaped, inferior margin U-shaped, lateral margin short, mesial margin elongated ( Figure 3 (b)); G1SA lacking raised rounded shoulder on external margin near G1TA-G1SA junction ( Figure 3 (a,b)); G2TA distinctly elongated, flagellum-like (G2TA/G2SA = 0.85) with pointed tip ( Figure 3 (d)). Figure 1. Vichai cyanalepou sp. nov. , holotype, adult J CW 38.5 mm, FMNH 7589, from Marojejy National Park,Sava region, northern Madagascar, whole animal: (a) dorsal view; (b) cephalothorax,ventral view. Scale bar: a = 10.8 mm; b = 5.5 mm. Figure 2. Vichai cyanalepou sp. nov. , holotype, adult J CW 38.5 mm, FMNH 7589, from Marojejy National Park, Sava region, northern Madagascar: (a) frontal view of carapace; (b) frontal view of right chela; (c) frontal view of left chela; (d) right cheliped merus, underside; (e) right cheliped merus, dorsal view; (f) right cheliped carpus, dorsal view; (g) third maxilliped, frontal view; (h) third maxilliped, posterior view; (i) mandible frontal view. Scale bar: a = 5.3 mm ; b, c = 8.0 mm; d = 5.3 mm ; e, f = 6.7 mm ; g, h = 3.3 mm ; i = 2.2 mm . Distribution Endemic to Madagascar . Vichai gen. nov. is currently known only from Marojejy National Park in the Sava Region in northern Madagascar . Etymology The genus is named in honour of Vichai Srivaddhanaprabha , the owner of the English Premier League football club Leicester City (LCFC) from 2010 until his death in a tragic helicopter crash at the King Power Stadium in October 2018 . Vichai was not only extremely mindful of the Leicester community and the LCFC supporters, but under his leadership the Football Club won the 2015–16 English Premier League title against all expectations, after starting the season as 5000/1 rank outsiders. The generic name, Vichai , is used as a Latin noun in nominative singular and treated as masculine. Remarks The genus Vichai is established for a new species, V. cyanalepou (see later). The recognition of the present new genus is based on phylogenetic and morphological evidence. The molecular phylogeny in Cumberlidge et al. (2020 , fig. 1, ′New genus E̍) indicates that V. cyanalepou sp. nov. is part of a unique basal clade that is clearly genetically separate from all other Malagasy genera. Mophologically, Vichai gen. nov. can be distinguished from the three other genera found in the Marojejy National Park (i.e. Foza Reed and Cumberlidge, 2006 , Hydrothelphusa A. Milne-Edwards, 1872 , and Marojejy Cumberlidge, Boyko and Harvey, 2002 ) as follows. The G1TA of Vichai gen. nov. is medium in length (G1TA/ G1SA = 0.3) and slim where the basal two-thirds are directed outward and the distal third curves upward ( Figure 3 (a–c)) vs a G1TA that is short (G1 TA/ SA = 0.25), straight, and broadly conical in Foza (see Leever et al. 2022 , fig. 7 g ,h). The exorbital and epibranchial teeth in Vichai gen. nov. are separated by a shallow notch ( Figure 1 (a)), whereas these teeth are separated by a deep cleft in Hydrothelphusa A. Milne-Edwards, 1872 (see Cumberlidge and Sternberg 2002 , fig. 1a–c; Cumberlidge et al. 2007 , figs 1, 16). Finally, the ambulatory legs of Vichai gen. nov. are short and stout (ΣP2–5/CW = 5.4) ( Figure 1 (a); Table 1 ) and its eyestalks and corneas are of normal length ( Figures 1 (a), 2(a)), whereas the ambulatory legs of Marojejy Cumberlidge et al. (2002) are elongated and slender (ΣP2–5/ CW = 7.0) and its eyestalks are short, taper distally, and have a reduced cornea (see Cumberlidge et al. 2002, fig. 2f). Figure 3. Vichai cyanalepou sp. nov. , holotype, adult J CW 38.5 mm, FMNH 7589, from Marojejy National Park, Sava region, northern Madagascar: (a) right G1, ventral view; (b) right G1, dorsal view; (c) right G1, superior view; (d) right G2, ventral view. Scale bar: a, b = 1.4 mm; c = 1.1 mm; d = 1.7 mm. The medium-sized anterior lobe on the terminal article of the mandibular palp of Vichai gen. nov. (MPAL/MPTA = 0.4) ( Figure 2 (i)) distinguishes it from three other Malagasy genera: Boreathelphusa ( Cumberlidge, 2010 ) , Madagapotamon Bott, 1955 and Skelosophusa Ng and Takeda (1994) . In all three of these genera, the anterior lobe on the mandibular palp is noticeably small (MPAL/MPTA = 0.2), and ledge-like (see Cumberlidge and Sternberg 2002 , fig. 4 h–l) rather than a broad rounded lobe as in Vichai gen. nov. ( Figure 2 (i)). Vichai gen. nov. can be distinguished from the remaining Malagasy genera as follows. The postfrontal crest of Vichai gen. nov. is incomplete and faint and does not traverse the entire carapace ( Figure 1 (a)), whereas the postfrontal crest is well defined and completely traverses the carapace in Agora (see Cumberlidge et al. 2020 ). The anterolateral regions of the carapace surface of Vichai gen. nov. are mostly smooth and only faintly carinated ( Figure 1 (a)), vs anterolateral regions of the carapace that have fields of well-defined carinae in Crosnautes (see Cumberlidge et al. 2021 , fig. 1a,b). The G1TA of Vichai gen. nov. is slim, tapers evenly, and curves upward distally ( Figure 3 (a,b)), vs a G1TA that is broadest at the midpoint and is straight along its length in Glabrithelphusa Meyer et al. (2014) (see Meyer et al. 2014 , figs 1a, 3a). The lateral carapace margin of Vichai gen. nov. is lined with small granules (Figure (1a)), vs a lateral margin that is lined with either small or medium-sized teeth in Malagasya Cumberlidge and Sternberg (2002) (see Cumberlidge and Sternberg 2002 , fig. 1e,f; Cumberlidge et al. 2020 , fig. 10a,c,e). Vichai gen. nov. can be also distinguished from Toamasina Leever et al. (2022) , as follows. The margins of the cheliped ischium of Vichai gen. nov. are smooth and rounded ( Figure 2 (d,e)), vs cheliped ischium margins that are lined with small teeth (see Leever et al. 2022 , fig. 4 g ,h); the exopod of the third maxilliped of Vichai gen. nov. has a mediumlength flagellum (~0.5× merus length) ( Figure 2 (g,h)), vs a third maxilliped exopod with an elongated flagellum (equal to the merus length) (see Leever et al. 2022 , fig. 2 f). In addition, the ambulatory legs of Vichai gen. nov. (P2–5) are short and stout (ΣP2–5/ CW = 5.4) ( Figure 1 (a); Table 1 ), vs ambulatory legs (P2–5) that are medium length (ΣP2–5/CW = 6.4) in Toamasina (see Leever et al. 2022 , table 3). Finally, Vichai gen. nov. can be distinguished from Vahatra Leever et al. (2022) by the characters of the chelipeds. The inner margin of the cheliped carpus of Vichai gen. nov. has a relatively small pointed distal tooth, a smaller acute proximal tooth, and granules between these teeth ( Figure 2 (f)), vs a cheliped carpus inner margin with a relatively larger, pointed distal tooth and a significantly smaller, acute proximal tooth, with no granules between the teeth in Vahatra (see Leever et al. 2022 , fig. 4f). The cutting edge of the fixed finger (pollex of propodus) of the major (left) chela of Vichai gen. nov. has one large molar tooth flanked by small teeth proximally ( Figure 2 (e)), whereas the fixed finger of the major (right) chela of Vahatra has four large molars proximally (see Leever et al. 2022 , fig. 4 g ,h). Further, the cutting edge of the movable finger (dactylus) of the major (left) chela of Vichai gen. nov. is lined with small teeth only and lacks large teeth ( Figure 2 (e)), whereas the cutting edge of the movable finger of the major (right) chela of Vahatra has two large teeth proximally and one large tooth midway (see Leever et al. 2022 , fig. 4 g ,h).