Lepidametria Webster, 1879

Salazar-Vallejo, Sergio I., Gonzalez, Norma Emilia & Salazar-Silva, Patricia, 2015, Lepidasthenialoboi sp. n. from Puerto Madryn, Argentina (Polychaeta, Polynoidae), ZooKeys 546, pp. 21-37 : 24-25

Taxon classification Animalia Phyllodocida Polynoidae

Lepidametria Webster, 1879

Lepidametria (incl. Nectochaeta von Marenzeller, 1892, Harmopsides Chamberlin, 1919, and Bouchiria Wesenberg-Lund, 1949).

Type species.

Lepidametria commensalis Webster, 1879, by monotypy.

Diagnosis

(modif. Webster 1879). Body long with up to 80 segments. Elytrae large, covering body or leaving a narrow dorsal surface uncovered; posterior region with elytra and cirri alternating every other segment. Tentaculophores with chaetae. Notopodia reduced, with fine notochaetae at least along anterior and median segments, rarely absent. Neuropodia projecting with several types of neurochaetae. Ventral surface often papillated.

Remarks.

Lepidasthenia and Lepidametria were regarded as synonyms by Gravier (1905), Potts (1910), Fauvel (1917), and Day (1962). Gravier indicated that the main difference was the presence of notochaetae in the latter but at the same time, he apparently rejected this difference by indicating that " Lepidasthenia elegans Grube a précisément une rame dorsale rudimentaire". [Transl.: Lepidasthenia elegans precisely has a rudimentary dorsal branch]. However, the diagnostic feature of missing notochaetae does not denote the presence of a notopodial lobe, but rather a complete absence of notochaetae. Consequently, we think that this is an important difference that can be used to easily separate these two genera. This same approach has been useful for separating other genera, and has been implied by the keys by Fauvel (1923:87), or directly by Fauchald (1977:59).

The pattern of the presence of elytra on posterior segments in Lepidametria and Lepidasthenia made Uschakov (1982), and Hanley and Burke (1991) regard them as distinct genera; i.e., Lepidametria has alternating elytra and cirri, whereas Lepidasthenia has elytra on every third segment in medial and posterior regions. Barnich and Fiege (2004) indicated they were following these conclusions and regarded Lepidametria as a member of Lepidonotinae , not Lepidastheniinae . Their reason was that in Lepidametria ( Barnich and Fiege 2004:864): "parapodia differ significantly in their shape from those of the members of the Lepidastheniinae . In the Lepidastheniinae neuropodia are well developed, rather elongate, and distinctly notched dorsally and ventrally, while in Lepidametria neuropodia are well developed, but shorter, and not distinctly notched, which is typical for the Lepidonotinae Willey, 1902".

It is unfortunate that there is no redescription for the type species of Lepidametria . The only illustrations available do not show this lepidastheniin notch; however, one figure shows that their neuropodia are not short ( Pettibone 1963:21, fig. 4g, k). In the original description Webster (1879:12) indicated (italics added): "Ventral ramus of foot stout, elongate, conical, widely excavated for the transmission of the setae, and obliquely truncated from above downward." This phrase in italics could be taken as equivalent to a notched neuropodium, however. The presence of chaetae in the tentaculophore, another non-lepidastheniin feature, was overlooked by Webster, and by Pettibone (1963:20), who regarded Lepidametria as a valid genus. Gardiner (1976, fig. 1n) illustrated the presence of chaetae in the tentaculophores, but his figure was based upon non-topotype specimens. After the syntype material was examined by one of us (PSS), we concluded that in Lepidametria commensalis there are chaetae in the tentaculophore and that parapodia differ from those present in Lepidastheniinae . Consequently, Lepidametria does not belong in this subfamily but in Lepidonotinae , as previously indicated by Barnich and Fiege (2004).