The Polydora cornuta complex (Annelida: Polychaeta) contains populations that are reproductively isolated and genetically distinct

Abstract

Abstract. We have collected evidence that the nominal species, Polydora cornuta Bosc 1802, contains at least three separate species in North America. Specimens of P. cornuta were collected in California, Florida, and Maine, raised in the laboratory, and assessed for reproductive compatibility, genetic similarity, gamete characteristics, and developmental rates. Reproductive crosses between each combination of sex and population revealed variable levels of hybridization at the level of fertilization. Percent fertilization was very low for all combinations (0–7%) except for California females crossed with Florida males (42%). In all interpopulation crosses, fertilized eggs arrested in cleavage and no viable larvae were produced. All pairwise comparisons of the studied populations showed significant differences in multiple reproductive traits. Mitochondrial cytochrome oxidase subunit I DNA sequences revealed large differences between Florida and California worms with a maximum likelihood genetic distance of d=0.860, while Florida and Maine worms were d=0.806, and California and Maine d=0.156. California and New Zealand worms were very similar genetically (d=0.010). These data strongly suggest that populations of P. cornuta in North America comprise a cryptic species complex composed of at least three distinct lineages.

First occurrence of the invasive alien species Polydora cornuta Bosc, 1802 (Polychaeta: Spionidae) on the coast of Greece (Elefsis Bay; Aegean Sea)

“…The origin of the Black Sea populations of this species has been linked to the introduction of the species from the Sea of Marmara through the Dardanelles Strait, or it could be an independent introduction from outside or inside the Mediterranean (KARHAN et al, 2008). Besides, as the populations of P. cornuta comprise a species complex composed of at least three separate species in the North America (RICE et al, 2007), the Mediterranean populations could similarly include several sibling species.…”

“…The genera Polydora has 52 valid species worldwide (ITIS: http://www.itis.gov/) and 10 valid species in Europe (ERMS: http://www.marbef.org/data/erms.php). The genera includes widespread 'cosmopolitan' species which have been later proved to actually include multiple cryptic species (RICE et al, 2007). Taxonomic confusion in the genus Polydora is a longstanding problem.…”

On the Occurrence and Established Populations of the Alien Polychaete Polydora cornuta Bosc, 1802 (Polychaeta: Spionidae) in the Sea of Marmara and the Bosphorus Strait (Turkey)

“…RASMUSSEN, 1973), as some studies have showed considerable variation in some features such as the presence of eyes and occipital antenna, and the appearance of the companion chaetae (RADASHEVSKY, 2005). Moreover, a recent study showed that the populations of P. cornuta comprise a cryptic species complex composed of at least three separate species in North America (RICE et al, 2008). Because of this confusion on the taxonomic status of P. cornuta and similar species and the difficulties in reexamination of old material, the exact dating of the first introduction of this species into the Mediterranean remains uncertain.…”

Morphology, 18S rRNA gene sequence and life history of a new Polydora species (Polychaeta: Spionidae) from northeastern Japan

“…Mor phological, biological and ecological approaches are mainly used to identify polydorid species, along with differences in methyl green staining (Read 2010) and information from allozyme analyses (Manchenko & Radashevsky 1993, 2002, Mustaquim 1988, Radashevsky & Pankova 2006. A molecular biological approach has been suggested in order to distinguish the species with closely similar morphology, but there have been few such studies in the Spionidae, particularly in polydorids (Bastrop et al 1998, Rice et al 2008.…”