Genus Bathytoshia Whitley, 1933

Bathytoshia Whitley, 1933:61 . Type species Dasyatis thetidis Ogilby, 1899; by original designation.

Definition. Gigantic dasyatids (adults to 210–260 cm DW) characterised by the following: robust, rhombic disc with pectoral-fin apex narrowly angular; snout obtuse and moderately elongate (1.5–2.5 times combined orbit and spiracle length); eye small and protruding slightly; nasal curtain broadly skirt shaped; mouth rather broad, with 3–7 oral papillae; tail firm and short to moderately elongate (length <1–2 times DW), its base broad to very broad and depressed; pelvic fins medium-sized, protruding slightly to greatly beyond disc; dorsal fold absent or forming a low ridge; ventral fold low with a short or long base; caudal sting not posterior on tail (distance from pectoral-fin insertion to caudal-sting base 2.2–3 times interspiracular width); skin smooth or rough and denticle band absent; median thorns absent or in a row extending along disc and onto tail, scapular thorns small or absent; tail spiny with bucklers and tubercles on dorsal midline of adults; dorsal colour largely plain; ventral surface white, disc margin sometimes dark; tail plain, usually black distally; marine, Atlantic and Indo– West Pacific.

Species. B. brevicaudata (Hutton, 1875), B. centroura (Mitchill, 1815), and B. lata (Garman, 1880) .

Remarks. Former junior synonym of Dasyatis (Kottelat, 2013) includes a small group of very large and widely distributed stingrays. Molecular data (G. Naylor, unpubl.) provides evidence that species complexes (A) Bathytoshia (as Dasyatis) brevicaudata and D. matsubarai Miyosi, 1939, and (B) Bathytoshia (as Dasyatis) lata, D. thetidis Ogilby, 1899, D. ushiei (Jordan & Hubbs, 1925), and eastern Atlantic stingrays identified as D. centroura (e.g. McEachran & Capapé, 1984), are populations of just two species (i.e. D. brevicaudata and D. lata). A western Atlantic species, Bathytoshia centroura (Mitchill, 1815), is not conspecific with Bathytoshia of the eastern Atlantic. The pelagic stingray Pteroplatytrygon violacea (Bonaparte, 1832), which clusters with these species (Fig. 1), is morphologically distinct from all other members of the family.