SPARKS: PHYLOGENY AND REVISION OF PARETROPLUS

摘要

A species-level phylogeny for Etroplinae is presented, based on the simultaneous analysis ofmorphological and nucleotide characters, and species of the endemic Malagasy genusParetroplus are taxonomically revised, including the description of two new species. Relativeto most other cichlid genera, Paretroplus is diagnosed by numerous anatomical features,including morphology of the gas bladder, neurocranium, oral jaws and dentition, andsuspensorium. Keys to the genera of Malagasy–South Asian cichlids and to the species ofParetroplus are provided. Paretroplus is endemic to Madagascar and is the sister genus toEtroplus, endemic to southern India and Sri Lanka. Together these two genera comprise thesubfamily Etroplinae. Paretroplus comprises 12 species, two of which are described herein asnew. Three morphologically distinct clades are recovered within Paretroplus, one comprising thecomparatively elongate, primarily riverine and rheophilic species P. damii, P. nourissati, P.tsimoly, and P. lamenabe, new species, the second comprising the deep-bodied, primarilylacustrine species P. polyactis, P. petiti, P. kieneri, P. maculatus, P. menarambo, P. maromandia,and P. dambabe, and the third comprising the shallow-bodied and highly mottled species P.kieneri and P. gymnopreopercularis, new species, which occur in both lentic and lotic habitats.Monophyly of Etroplinae and Etroplus are also discussed and diagnostic anatomical features arepresented for both clades. The sister-group relationship between Etroplus and Paretroplusrepresents a well-corroborated transoceanic link within Cichlidae, a pattern congruent with theMesozoic fragmentation of Gondwana. The anterior of the gas bladder is highly modified inEtroplinae, reaching its most derived configuration in Paretroplus, in which multiple,structurally complex and rigid anterior bullae expand into large exoccipital recesses, forminga mechanical (= otophysic) connection between the gas bladder and inner ear. Evolution of thegas bladder, and its function in conferring increased hearing ability, is discussed in terms of thephylogenetic information this structure provides for reconstructing hypotheses of relationshipswithin Cichlidae.