Symbiotic Siphonostomatoida (Copepoda) of the hammerhead shark species Sphyrna zygaena (Carcharhiniformes: Sphyrnidae) and stingray Dasyatis pastinaca (Myliobatiformes: Dasyatidae) off the Canary Islands, with a re-description of Pseudocharopinus pillaii Kabata, 1979

The biology, including accompanying ectoparasitic fauna, remains unstudied for several elasmobranchs off the Canary Islands in spite of concerns over their conservation. Within this region, this is the first report of copepod associations with these fishes. Twenty smooth hammerhead sharks, Sphyrna zygaena, and one common stingray, Dasyatis pastinaca, were inspected for symbionts on their body surface. Symbiotic siphonostomatoids were collected from 18 S. zygaena hosts and represent two different species, i.e., Alebion crassus (Caligidae) and Pandarus cranchii (Pandaridae). A high prevalence of 90% and a mean infection of 8.3 individuals per infected host were exhibited by A. crassus, while only a single P. cranchii was collected. Both these findings represent new geographical records. Additionally, one free-ranging common stingray Dasyatis pastinaca was opportunistically inspected and 11 Pseudocharopinus pillaii (Lernaeopodidae) collected which constitutes a new host record and a new geographical record. A re-description with detail regarding the morphology of the appendages is provided for the first time. Due to the morphological similarity between P. pillaii and P. malleus, a molecular analysis of the partial mitochondrial DNA cytochrome oxidase I gene was done in an attempt to determine if there is molecular divergence between the two species. This provided an estimate of the phylogenetic relationships amongst four Pseudocharopinus species (P. bicaudatus, P. pteromylaei, P. malleus, and P. pillaii) with Charopinus dubius as an outgroup as an alternative hypothesis to compare with the previous morphological topology estimated for all Pseudocharopinus species.

Automated summary

The biology, including accompanying ectoparasitic fauna, remains unstudied for several elasmobranchs off the Canary Islands in spite of concerns over their conservation. This study reports on copepod associations with smooth hammerhead sharks and common stingrays for the first time, as well as the discovery of new geographical records for symbiotic siphonostomatoids. The study also provides a re-examination of the morphology of Pseudocharopinus pillaii and a molecular analysis of its genetic relationship with other Pseudocharopinus species.