Redescription of Pseudanthobothrium hanseni Baer, 1956 and description of P. purtoni n. sp. (Cestoda: Tetraphyllidea) from different pairs of rajid skate hosts, with comments on the host-specificity of the genus in the northwest Atlantic

Abstract

During a parasitological survey of Leucoraja erinacea, L. ocellata, Malacoraja senta and Amblyraja radiata from Passamaquoddy Bay and waters surrounding the West Isles of the Bay of Fundy, NB, Canada, seven species of cestodes were recovered. Examination of these skates revealed the presence of two distinct species of Pseudanthobothrium Baer, 1956: one was retrieved from M. senta and A. radiata, identified as P. hanseni Baer, 1956 and redescribed herein; the other was retrieved from L. erinacea and L. ocellata and differs from previously described species. The new species is described herein as P. purtoni n. sp. on the basis of the degree of apolysis, the maximum width of the strobila, the length of the cirrus-sac and the number of testes. Additionally, the distinctiveness of both species of Pseudanthobothrium is supported by the characterisation of a 643 base-pair nuclear marker, which includes most of the D2 variable region of the large subunit ribosomal DNA (LSU). The recovery of two different tetraphyllidean species, each from two different host species, challenges the oioxeny (strict host-specificity) of echeneibothriine cestodes and can be explained, at least in part, by the similarities in diet and substrate preference within each host pair.

Determinants of Host Specificity and Comments on Attachment Site Specificity of Tetraphyllidean Cestodes Infecting Rajid Skates from the Northwest Atlantic

“…Randhawa et al (2007) assessed the host specificity of Echeneibothrium vernetae Euzet, 1956, Pseudanthobothrium hanseni Baer, 1956, and Pseudanthobothrium purtoni (Randhawa et al, 2008) using anatomical observations and partial sequence data of a variable region (D2) from the large subunit ribosomal DNA (LSU). We established that adult specimens of all 3 species infect ecological pairs (McEachran et al, 1976) of rajid host species.…”

“…The specificity of tetraphyllideans has been attributed to: (1) morphological adaptations of the scolex to the host mucosa (Williams, 1960(Williams, , 1966(Williams, , 1968a(Williams, , 1968b; (2) physiological adaptations of hosts to the parasites, such as serum factors (McVicar and Fletcher, 1970); and (3) ecological factors, such as substrate preference and diet of the hosts (Randhawa et al, 2008). Williams (1960) described the spiral valve mucosa of 3 rajid species and 10 species of elasmobranchs (Williams, 1968a) and concluded that the differences in topography of the gut mucosa contribute to the observed specificity of tetraphyllidean cestodes.…”

“…McVicar and Fletcher (1970) exposed Acanthobothrium quadripartitum Williams, 1968, a parasite specific to Leucoraja naevus in the North Sea, to Amblyraja radiata and L. naevus blood sera and concluded that complement and/or a specific antibody response are responsible, at least partially, for the host specificity of this parasite. Using ecological data (McEachran and Musick, 1975;McEachran et al, 1976;Packer et al, 2003aPacker et al, , 2003bPacker et al, , 2003cPacker et al, , 2003d and gut contents (Randhawa et al, 2008), we have determined that host substrate preference and corresponding prey biota are possible factors relating to the specificity, and lack of strict specificity, of Pseudanthobothrium spp. and Echeneibothrium spp.…”

“…and Echeneibothrium spp. from the region of the West Isles of the Bay of Fundy, New Brunswick (NB), Canada (Randhawa et al, 2008).…”

Identification of non-indigenous marine macroalgae from New Zealand aquaria outlets

“…PCR conditions were 948C for 3 min, 35 cycles of 948C for 1 min, 578C for 30 s, 728C for 2 min and a final extension of 728C for 7 min. The Rhodophyta specimens were amplified with the primer pair T01N and T13N (Randhawa et al 2008). These primers amplify approximately 1100 bp of the 5?…”