Date of Completion

Spring 5-1-2016

Project Advisor(s)

Janine Caira; Elizabeth Jockusch; Andrew Bush

University Scholar Major

Ecology and Evolutionary Biology

Disciplines

Evolution

Abstract

Collection of new material from the bamboosharks Chiloscyllium indicum Gmelin, 1789 and Chiloscyllium hasseltii Bleeker, 1852 from Indonesian and Malaysian Borneo prompted reevaluation of the identity and host associations of the cestode genus Carpobothrium Shipley & Hornell, 1906. Light microscopical examination of whole mounts, histological sections, and egg preparations, in combination with scanning electron microscopy of scoleces, led to redescription of the type species Carpobothrium chiloscyllii Shipley and Hornell, 1906 from C. indicum, as well as description of a new species from C. hasseltii. Examination of some of Southwell’s material identified as C. chiloscyllii from the batoid hosts Urogymnus asperrimus Bloch & Schneider, 1801 and Rhynchobatus djeddensis Forsskål, 1775 in Sri Lanka, confirmed evidence from molecular work suggesting that these cestodes, which also bear pouch-like bothridia, represent a distinct group of cestodes from those parasitizing bamboosharks. Collection of new material from hosts Rhina ancylostoma Bloch & Schneider, 1801, Himantura uarnacoides Bleeker, 1852, and Himantura pastinacoides Bleeker, 1852 led to the formal erection of this novel batoid-hosted cestode genus as Orallobothrium n. gen. Light microscopical examination of whole mounts and scanning electron microscopy of scoleces resulted in the description of 3 novel species. Sequence data from the D1–D3 region of the 28S rDNA gene support recognition of the 3 species described here. The positions of both Carpobothrium and the new genus described here within the larger “tetraphyllidean” tree were found to be phylogenetically unstable across analyses. These and other differences in tree topology across analyses highlights the need for additional taxa and data to be applied to the problem if these relationships are ever to be fully elucidated.

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