Katria, STIASSNY & SPARKS, 2006

STIASSNY, MELANIE L. J & SPARKS, JOHN S, 2006, Phylogeny and Taxonomic Revision of the Endemic Malagasy Genus Ptychochromis (Teleostei: Cichlidae), with the Description of Five New Species and a Diagnosis for Katria, New Genus, American Museum Novitates 3535 (1), pp. 1-56 : 52

Katria , new genus

DIAGNOSIS: A ptychochromin genus diagnosed by a unique pigmentation and coloration pattern consisting of two prominent black vertical bars on an iridescent golden background (plate 1H and 2F), the presence of reduced anterior gas bladder horns that do not approach or contact the exoccipital region of the neurocranium (Character 17: 0, fig. 3A), a reduced number of gill rakers on the lower limb of the first gill arch (8–9 [mode 8] vs. 8–12 [mode 10] in other ptychochromins), an elevated vertebral count (29–30 [mode 30] vs. 26–28 [mode 27] in Ptychochromis ), and a more slender caudal peduncle (length to depth ratio modally 1.4 vs. 0.6–1.2 in Ptychochromis and Ptychochromoides ). Katria is readily differentiated from Ptychochromoides by the presence of two toothrows (fig. 7B) on Pb2 (vs. 1; Character 19:1), and from Ptychochromis by the absence (fig. 7B) of a ‘‘free’’ toothplate associated with Ep2 (vs. presence of ‘‘free’’ Ep2 toothplate; Character 10:1, Fig 7A ).

TYPE SPECIES: Katria katria ( Reinthal and Stiassny, 1997) ; by monotypy.

REMARKS: At the time of its original description, Reinthal and Stiassny (1997) were unable to provide unambiguous morphological support for their placement of katria in the genus Ptychochromoides . They proposed that the presence of a pronounced nuchal hump in adult katria and in Ptychochromoides , and the possession of an elevated vertebral count (relative to that of Ptychochromis ) were suggestive of relationship, but cautioned that ‘‘further systematic analysis may necessitate an eventual reassignment and generic reorganization’’. The molecular analyses of Sparks (2004) and Sparks and Smith (2004) provide strong support for the placement of Ptychochromoides katria as the sister taxon to a monophyletic Ptychochromis (e.g., in the study of Sparks and Smith [2004], which comprised fragments of two mitochondrial and two nuclear genes, this sister group relationship is robustly supported [Bremer support: 11; jackknife 100%]). The current study corroborates that placement and, consequently, we remove katria from Ptychochromoides and place it in Katria new genus. Uniquely among ptychochromins, Katria shares with Ptychochromis the following synapomorphic features: Cb4 bears a characteristically elongate process and deeply rounded indentation on its inner margin (fig. 4C; Character 6:1); hypertrophy of the laterosensory canal system of the neurocranium, preopercle, mandible, and infraorbital series (Character 7:1, fig. 8E); two supraneural elements located anterior to the first neural spine (fig. 3A; Character 8:1); and a well-developed, expansive and dorsally elevated lateral ethmoid process on the dorsal margin of the palatine head (fig. 6E; Character 9:1). Katria lacks the four apomorphic features identified herein as diagnostic of its sister taxon, Ptychochromis (i.e., presence of a ‘‘free’’ toothplate associated with Ep2, Character 10:1; IO2 excluded from the orbit by IO3, Character 11:1; presence of a palatine groove, Character 12:1; ventral displacement of the palato-palatine ligament insertion, Character 13:1).

Figures

Fig. 7. Isolated upper pharyngeal jaw (ventral view) of (A) Ptychochromis onilahy (MNHN 1962-0201) and (B) Katria katria (AMNH 93701). Ptychochromis is diagnosed among cichlids by the presence of a ‘‘free’’ toothplate associated with, but not fused to, the second epibranchial bone (indicated by arrow).