Cryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa.

John Sullivan,Sebastien Lavoue,Carl D Hopkins

doi:10.3897/zookeys.561.7137

Abstract

We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrus ogoouensis, new species, is differentiated from its single congener, Cryptomyrus ona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In Cryptomyrus ona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea.

Highlights

Mormyrids are nocturnally active fishes endemic to the continental freshwaters of Africa that produce weak electric impulses from a muscle-derived organ located in the caudal peduncle, anterior to the caudal fin
Among mormyrids of Lower Guinea, this EOD is most similar to that recorded from Hippopotamyrus castor from Cameroon (Hopkins et al 2007), but dissimilar to that of every other species recorded so far in Gabon
Details of the EOD are provided in the species description below, and the recording is available in the archive of the Macaulay Library at the Cornell Lab of Ornithology under accession number ML197475

Summary

Introduction

Mormyrids are nocturnally active fishes endemic to the continental freshwaters of Africa that produce weak electric impulses from a muscle-derived organ located in the caudal peduncle, anterior to the caudal fin. In many mormyrids the waveform of each short (0.2–12 millisecond) pulse encodes the species identity and sex of the signaler while patterns in the timing of pulses convey motivational states (Baker et al 2013; Hopkins 1986, 1999; Hopkins and Bass 1981). Due to their frequent speciesspecificity, recorded EOD waveforms can provide valuable characters for the taxonomy of these fishes (Sullivan et al 2002; Arnegard and Hopkins 2003; Hopkins et al 2007). The division of Mormyridae into two subfamilies, Mormyrinae (19 genera) and Petrocephalinae (one genus), is supported by both morphological and molecular evidence (Taverne 1972; Sullivan et al 2000; Lavoué et al 2003)

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Results

Conclusion