Redescription of Alitta succinea (Leuckart, 1847) and reinstatement of A. acutifolia (Ehlers, 1901) n. comb. based upon morphological and molecular data (Polychaeta: Nereididae)

Abstract

The nereidid worm Alitta succinea (Leuckart, 1847), described from Western Germany, has been considered by some authors as a widespread and alien invasive species, or else as a group of morphologically indistinguishable species. Neither idea has yet been supported by critical taxonomic revisions of relevant material. Most characterizations of A. succinea were based upon a mixture of morphological features from specimens from the type locality and from other regions. Moreover, four species described from America are considered junior synonyms of A. succinea, including Nereis acutifolia Ehlers, 1901, described from the eastern tropical Pacific. The type material of the latter species has not been reviewed since its description. We re-examined type and topotype materials of A. succinea and N. acutifolia including atokous and epitokous specimens. In addition, newly collected specimens were used to evaluate genetic divergence between both species using the mitochondrial gene COI. Alitta succinea is redescribed from type material and specimens from Germany. We rejected the recent placement of the species in Neanthes and we transferred it to Alitta. Further, we refuse the synonymy of N. acutifolia with A. succinea due to morphological and molecular differences. Consequently, we regard Alitta acutifolia n. comb. as a valid species, and the supposed introduction and the alien status of A. succinea along the Mexican and Central American Pacific shores are rejected.

Redescriptions of Nereis oligohalina (Rioja, 1946) and N. garwoodi González-Escalante & Salazar-Vallejo, 2003 and description of N. confusa sp. n. (Annelida, Nereididae)

“…The anterior-most rows have P-bars alternating with conical or pyramidal paragnaths in a similar way as in Pseudonereis (Fig. 6D–F), which has been also reported for Alitta (Villalobos-Guerrero and Carrera-Parra 2015). Therefore, P-bars are not an exclusive feature of Pseudonereis as Bakken et al (2009) concluded.…”

“…6H); these modified structures were regarded as melted paragnaths (Bakken et al 2009). However, Glasby et al (2011) suggested limiting use of the term for conical paragnaths mounted on a plate-like basement as occurs in Neanthes pachychaeta (Fauvel, 1918), and Villalobos-Guerrero and Carrera-Parra (2015) found paragnaths on a soft basement in Alitta acutifolia (Ehlers, 1901). Because neither a basement is present in Nereis confusa sp.…”

Reproductive biology of Alitta succinea (Annelida: Nereididae) in a Brazilian tropical lagoon

“…It is likely that the male individuals described by Villalobos-Guerrero (2012) and Villalobos-Guerrero & Carrera-Parra (2015) were in earlier stages of epitoky or, perhaps, A. succinea comprises a species complex. There are no reports of the presence of serrated papillae in the ventral cirri in other studies of Alitta species, or other genera of the family.…”

“…This species can be found in a variety of marine and estuarine intertidal to subtidal substrates, including infaunal and epifaunal locations, sand and mud bottoms, seagrass meadows, and rocky benthic areas (Pardo & Dauer 2003;Gillet et al 2011). The species is semelparous, and individuals die soon after a single reproductive event (Villalobos-Guerrero 2012).…”

“…Females sporadically move in circles for a few seconds and then begin to release pheromones. Males may survive a little longer and can search for new females (Hardege 1999;Villalobos-Guerrero 2012). During spawning, a single female can attract up to ten males.…”