Dramatic phenotypic plasticity within species of

Authors: Terrence L Miller Thomas H Cribb

Publish Date: 2013/09/19

Volume: 86, Issue: 2, Pages: 101-112

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Abstract

A survey of IndoPacific lutjanids of the subfamily Caesioninae revealed the presence of Siphodera gurukun Machida 1910 and two new cryptogonimid taxa from off Heron and Lizard Islands on the Great Barrier Reef Australia Ningaloo Reef Western Australia and Rasdhoo Atoll Maldives A combined morphological and genetic characterisation of these species shows that they form a clade distinct from the typespecies of Siphodera Linton 1910 S vinaledwardsii Linton 1901 and warrants the proposal of a new genus Here we propose Siphomutabilus n g and transfer Siphodera gurukun Machida 1986 as the typespecies Siphomutabilus gurukun Machida 1986 n comb Siphodera aegyptensis Hassanine Gibson 2005 is transferred to Siphomutabilus as S aegyptensis Hassanine Gibson 2005 n comb based on morphological and ecological similarities Siphomutabilus raritas n sp is described from Caesio cuning Bloch off Lizard Island and S bitesticulatus n sp is described from Pterocaesio marri Schultz off Heron Island The two new species are unique in that they have two testes making their morphology broadly consistent with that of Metadena Linton 1910 yet the molecular analyses conducted here indicates that they are unequivocally united with Siphomutabilus gurukun which has multiple testes to the exclusion of Metadena lutiani Yamaguti 1942 which was sequenced here The dramatic phenotypic plasticity observed among such closely related species of Siphomutabilus suggests a secondary modification of what is generally considered a robust generic diagnostic character within this and other digenean families highlighting the need for a combined morphological and molecular diagnostic approach when characterising these taxa Siphodera Linton 1910 is amended to include just two species the typespecies S vinaledwardsii Linton 1901 Linton 1910 and S cirrhiti Yamaguti 1970 which are distinguished by their lack of oral spines and multiple testes that are primarily extracaecal Siphodera ghanensis Fischthal Thomas 1968 is considered a species incertae sedis here based on significant morphological and ecological differences compared with species of Siphodera and Siphomutabilus n gThis study was funded by and is a contribution from the Australian node of the CReefs global research initiative Grant Number 209/29 a partnership between the ABRS BHP Billiton the Great Barrier Reef Foundation the Census of Marine Life and the Australian Institute of Marine Science AIMS The CReefs Australia Project is generously sponsored by BHP Billiton in partnership with The Great Barrier Reef Foundation the Australian Institute of Marine Science the Australian Biological Resources Study and the Alfred P Sloan Foundation CReefs is a field programme of the Census of Marine Life We gratefully thank the staff of the Heron and Lizard Island research stations for their support and hospitality during our many long stays We also thank Dr Robert Konecny and Julia Lorber for helping to organize the trip to the Maldives and for their assistance in the field We are grateful to the Research Service and International Relations Office of the University of Vienna for assistance in financing the trip to Rasdhoo Atoll Maldives Dr Reinhard Kikinger kindly gave us access to his laboratory at the Kuramathi Biological Field Station to conduct fish necropsies and extended his generous hospitality to us during our stay

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