Browsing by Author "Chakrabarty, Prosanta."
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Item Description of a new species of ponyfish (Teleostei, Leiognathidae, Equulitini, Photolateralis) from the Gulf of Oman. (American Museum novitates, no. 3929)(American Museum of Natural History., 2019-06-19) Sparks, John S.; Chakrabarty, Prosanta.A new species belonging to the leiognathid genus Photolateralis, collected from the coastal waters of Oman, is described herein. Photolateralis is unique among leiognathid genera in possessing a species-specific translucent midlateral flank stripe that may be comprised of either multiple independent translucent windows (P. stercorarius, P. moretoniensis, and the new species) or a continuous translucent lateral band (P. antongil). Photolateralis polyfenestrus, new species, is distinguished from congeners by the presence of a short, composite midlateral stripe comprised of three small, rounded translucent windows (vs. numerous windows in both P. stercorarius and P. moretoniensis, or a continuous translucent stripe in P. antongil), and that is confined to the midflank (vs. extending a majority of the length of the flank in congeners). The new species is further distinguished from both P. moretoniensis and P. antongil by a shallower body, and from both P. stercorarius and P. moretoniensis by a pigmentation pattern above the lateral midline comprised primarily of larger rounded blotches (vs. smaller sinuous lines and markings comprising a vermiculated pattern). Photolateralis polyfenestrus is characterized by a lower jaw that is deep and convex in lateral view (vs. mostly straight in congeners, excluding P. antongil), and that forms an angle of between 60°-70° to horizontal (vs. less than 45° in congeners, excluding P. antongil). The only other species of Photolateralis reported from the western Indian Ocean is P. antongil, to date only known from the coastal waters of Madagascar, whereas both P. stercorarius and P. moretoniensis have ranges restricted to the western Pacific and extending into the eastern Indian Ocean.Item Diagnoses for Leiognathus Lacepède 1802, Equula Cuvier 1815, Equulites Fowler 1904, Eubleekeria Fowler 1904, and a new ponyfish genus (Teleostei, Leiognathidae) ; American Museum novitates, no. 3623(New York, NY : American Museum of Natural History, 2008) Chakrabarty, Prosanta.; Sparks, John S.Recent phylogenetic work on ponyfishes has delimited and revealed the interrelationships of major leiognathid clades. To begin to recognize a monophyletic taxonomy for Leiognathidae we diagnose, delimit, and describe a number of ponyfish genera to reflect our current knowledge of their phylogenetic history. Equula Cuvier, 1815, is resurrected from synonymy with Leiognathus Lacepède, 1802, and comprises E. fasciata and E. longispinis. Members of Equula, the sister group to all other members of Leiognathidae, are large-bodied ponyfishes characterized by conspicuous round yellow blotches on the flank. The genus Leiognathus Lacepède, 1802, the sister group to the remaining members of Leiognathidae less Equula, is herein restricted to a clade comprising Leiognathus equulus, L. robustus, and L. striatus. The subgenus Equulites Fowler, 1904, comprising E. leuciscus, E. klunzingeri, and E. laterofenestra, is removed from synonymy with Leiognathus and is elevated to generic rank. The subgenus Eubleekeria Fowler, 1904 is removed from synonymy with Leiognathus and is likewise elevated to generic rank. Eubleekeria encompasses the "Leiognathus" splendens species complex, which is recovered as the sister group to Photopectoralis. To remedy the paraphyly of the remaining species placed within Leiognathus we describe a new genus, Karalla, which is recovered as the sister group to Nuchequula.Item Phylogeny and taxonomic revision of Nuchequula Whitley 1932 (Teleostei, Leiognathidae), with the description of a new species ; American Museum novitates, no. 3588(New York, NY : American Museum of Natural History, 2007) Chakrabarty, Prosanta.; Sparks, John S.Nuchequula Whitley 1932, previously considered a subgenus of Leiognathus Lacep‡ede 1802, is elevated to generic rank. Nuchequula is diagnosed by the presence of a distinct saddle-shaped nuchal marking and by the presence of a pigment-free, mitten-shaped region posteroventral to the pectoral-fin base. The genus comprises five species, N. blochii, N. pan, N. nuchalis, N. decora, and a new species described herein. Nuchequula mannusella, new species, is distinguished from its congeners by a unique pigmentation pattern on the dorsal fin and morphology of the lower jaw. Redescriptions are provided for the other species. A phylogenetic analysis based on morphological characters, including features of the light-organ system, indicates that Nuchequula is monophyletic.Item Revision of the endemic Malagasy cavefish genus Typhleotris (Teleostei, Gobiiformes, Milyeringidae), with discussion of its phylogenetic placement and description of a new species. (American Museum novitates, no. 3764)(American Museum of Natural History., 2012-12-11) Sparks, John S.; Chakrabarty, Prosanta.Troglobitic cavefishes of the genus Typhleotris, endemic to coastal southwestern Madagascar, are taxonomically reviewed and a new darkly pigmented species, Typhleotris mararybe, is described from an isolated karst sinkhole on the coastal plain below the Mahafaly Plateau. The new species, known only from Grotte de Vitane (Vitany) near the town of Itampolo, is unique among blind cavefishes in being uniformly darkly pigmented, rather than fully depigmented or exceptionally light in coloration. In addition to its dark coloration (vs. depigmented, translucent white body in congeners), the new species can be distinguished from its two congeners, Typhleotris madagascariensis and T. pauliani, by the sculpted, bony (vs. fleshy) appearance of its head with strongly protruding lateral ethmoid, sphenotic, and pterotic bones, and an elevated vertebral count.