Karalla, Chakrabarty & Sparks, 2008

Chakrabarty, Prosanta & Sparks, John S., 2008, Diagnoses for Leiognathus Lacepède 1802, Equula Cuvier 1815, Equulites Fowler 1904, Eubleekeria Fowler 1904, and a New Ponyfish Genus (Teleostei: Leiognathidae), American Museum Novitates 3623 (1), pp. 1-12 : 7-8

Karalla , new genus

Figure 6

Clade G, in part: Sparks et al. 2005.

TYPE SPECIES: Karalla daura ( Cuvier, 1829) .

OTHER INCLUDED SPECIES: Karalla dussumieri (Valenciennes, in Cuvier and Valenciennes, 1835).

DIAGNOSIS: Members of Karalla are distinguished from all other leiognathids by either the presence of a deep golden coloration on the flank or a weakly retrognathous lateral snout outline.

ETYMOLOGY: Karalla is the local name for ponyfishes in Sri Lanka and the surrounding region where members of this genus commonly occur. This generic epithet is genderneutral.

REMARKS: Karalla can be further distinguished from other leiognathids by the combination of a scaled nuchal region, an elongate rhomboid body, and the presence of two welldeveloped (vs. weak) prongs on the anterodorsal margin of the cleithrum (fig. 7). The presence of two prongs on the anterodorsal margin of the cleithrum is a synapomorphy of Leiognathidae ; however, this feature is more prominent in Karalla than most other genera (fig. 7). Members of Karalla also possess a distinct golden or deep yellowish-green coloration in life that differs from the bright yellow coloration of some species of Nuchequula .

The relationship between Karalla and Nuchequula was unresolved in the analysis of Sparks et al. (2005; Karalla daura was recovered as more closely related to Nuchequula than to K. dussumieri ); however, members of both genera were recovered together as a monophyletic group in that study. Nuchequula is recovered with strong support as the sister group to Karalla in the phylogenetic analysis of Chakrabarty et al. (MS). This clade comprising Karalla and Nuchequula is in turn recovered as the sister group to Photoplagios (fig. 1). Karalla can be easily distinguished from Nuchequula by the absence of a prominent nuchal marking, whereas the presence of a nuchal marking is a synapomorphy of the latter genus ( Chakrabarty and Sparks, 2007).

Karalla daura can easily be distinguished from all other leiognathids by the presence of enlarged fleshy lips and by the presence of a broad, golden horizontal stripe along the midline of the flank, which surrounds the entire lateral line from the orbit to the caudal peduncle, and is as deep as the arc of the lateral line vertically (fig. 6A). In contrast, K. dussumieri lacks a distinct golden stripe. Instead, a diffuse golden coloration is present on the flank punctuated by dark, yellow-green vermiculate lines over the dorsal half of the body. In addition, K. daura also possesses a large dark blotch on the spinous dorsal-fin membrane, a feature lacking in K. dussumieri (fig. 6B).