Syndesmis aethopharynx Westervelt & Kozloff, 1990 (Rhabdocoela: Umagillidae): a revisitation supported by scanning electron microscopy and molecular analyses

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Cavaleiro, FI (Author) Other; Rangel, LF (Author) Other; Frade, DG (Author) Other; Santos, MJ (Author) FCUP

Journal

Title: Systematic Parasitology

Vol. 94

Pages: 1007-1017

ISSN: 0165-5752

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 2 Citations

Other information

Authenticus ID: P-00N-46R

DOI: 10.1007/s11230-017-9754-0

Abstract (EN): Species of Syndesmis Francois, 1886 are rhabdocoel platyhelminths typically found in echinoids. Our knowledge of this group is based on old and insufficient studies, generally representing light microscopy-based species descriptions. Syndesmis aethopharynx Westervelt & Kozloff, 1990 is an understudied endosymbiont of Paracentrotus lividus (Lamarck), which is likely to have been confused with the type-species, i.e. Syndesmis echinorum Francois, 1886, in the literature. In this work, S. aethopharynx is revisited based on new data on surface morphology and phylogeny and basic ecological data are provided. Scanning electron microscopy analysis revealed that the whole ventral region of the worm is equipped with cilia, which supports the assumption that the unciliated epidermal area reported for some species of umagillids, likewise endosymbiotic in echinoderms, is an apomorphy. Following the results of the molecular phylogenetic analysis, species of Syndesmis are closely-related to symbionts of other echinoderms, i.e. holothurians, and like them, may have evolved from some free-living or symbiotic Provorticidae ancestor. Syndesmis spp. may stand for a key group in studying the evolution of feeding strategies in rhabdocoels, as their phylogenetic position is between intestinal and coelomic symbionts, and since both the digestive tube and perivisceral fluid were recorded as sites of infection. The infection levels were low, likely reflecting the aggregated distribution of the host and the fragile nature of the symbiont.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11