A review of the currently recognised opecoelid cercariae, including the identification and emergence ecology of Cercaria capricornia XII (Digenea: Opecoelidae) from Nassarius olivaceus (Gastropoda: Nassariidae) in Central Queensland, Australia.
A new opecoelid cercaria, Cercaria capricornia XII, is reported from Nassarius olivaceus in Capricornia, Central Queensland, Australia. Combined molecular and morphological data indicate that this cercaria is a member of the subfamily Opecoelinae. Cercaria capricornia XII is the first known opecoeline cercaria reported from a nassariid gastropod. Cercaria capricornia XII can be distinguished from other opecoelid cercariae by the combination of the presence of a 2-pointed stylet, body length and width, and the size of the tail. The emergence pattern for C. capricornia XII in captivity was erratic; rapid emergences of thousands of cercariae were interspersed by periods that sometimes exceeded a month in which no emergence occurred. There was no detectable pattern to or stimulus of the emergence. The molluscan host range of opecoelids is analysed in detail. Gastropods from the Buccinoidea, Cerithioidea and Rissooidea are hosts to both opecoeline and plagioporine cercariae, but the dominant subfamily infecting the Cerithioidea and Rissooidea is the Plagioporinae. The dominant marine host gastropod superfamily for opecoeline cercariae is the Buccinoidea; the family Nassariidae is contained in the Buccinoidea. The range of gastropod superfamilies known as hosts of plagioporines is much broader than that for opecoelines, which may be explained by the relative size of the two opecoelid families and perhaps by indications that the Plagioporinae is polyphyletic.
Central Queensland University, Academic Learning Services Unit, Bruce Highway, North Rockhampton, Queensland 4702, Australia. Electronic address: l.barnett@cqu.edu.au.
Leonie J
LJ
Barnett
School of Marine and Tropical Biology, James Cook University, Cairns, Queensland 4870, Australia. Electronic address: terry.miller1@jcu.edu.au.
Terrence L
TL
Miller
School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia. Electronic address: t.cribb@uq.edu.au.
Thomas H
TH
Cribb
D000818:Animals; D001315:Australia; D058487:Cercaria / Q000235:genetics* / Q000302:isolation & purification*; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D049851:Gastropoda / Q000469:parasitology*; D006790:Host-Parasite Interactions; D010802:Phylogeny
D021903:DNA, Ribosomal Spacer
Capricornia; Cercaria capricornia; ITS2 rDNA; Internal transcribed spacer 2; Nassarius olivaceus; Opecoelidae