Sigambra bassi (Hartman, 1947)

Salazar-Vallejo, Sergio I., Rizzo, Alexandra E., Leon-Gonzalez, J. Angel de & Brauko, Kalina M., 2019, Four new Caribbean Sigambra species (Annelida, Pilargidae), and clarifications of three other Sigambra species, ZooKeys 893, pp. 21-50 : 21

Sigambra bassi (Hartman, 1947) Fig. 1

Ancistrosyllis bassi Hartman, 1945: 6 (contents), 9 (substrate), 15 (non-diagnostic characters), nomen nudum.

Ancistrosyllis bassi Hartman, 1947: 501-504, pl. 61, figs 1-7; Hartman 1951: 36-38, pl. 11, figs 1-6 (figures rearranged from Hartman 1947).

Sigambra bassi : Pettibone 1966: 186, fig. 16, comb. nov.

Type material.

Holotype (LACM 142), Gulf of México, southwestern Florida, Lemon Bay, Chadwick Beach (26°55'25"N, 82°21'40"W), sandy shore, low tide, 17 Jan. 1938, O. Hartman, coll. Paratype (LACM 1549), northwestern Atlantic, Beaufort, Bogue Sound, North Carolina, near US Fisheries Laboratory on Pivers Island (34°43'11"N, 76°40'19"W), sandy shore, 6 Jun. 1940, O. Hartman, coll.

Additional material.

Northeastern Pacific, Los Angeles. Non-type specimen (LACM 6614), opposite Berth 79, at old Municipal Fish Market, in mid-channel, Sta. LA-26 (33°33'17"N, 118°16'34"W), 12 m, black mud, 14-15 Jun. 1954, D.J. Reish et al. coll.

Clarification.

The holotype ( Fig. 1A ) was found in the Gulf of México side of Florida, whereas the paratype ( Fig. 1B ) was found in North Carolina. Both specimens are colorless, without any trace of pigmented glands. An additional specimen ( Fig. 1C ) was included in the same species, but it was collected in Los Angeles Harbor, and it has some brownish glands in both dorsal tentaculophores and dorsal cirri of chaetiger 1. There are some other differences between these specimens. For example, in the holotype the interpalpal area is slightly projected anteriorly and its margins are slightly divergent posteriorly, the lateral antennae are three times longer than wide, and the lateral antennal depressions are markedly divergent and expanded, such that the anterior region is wider than posterior one. In the paratype the interpalpal area is tapered, reduced anteriorly, with its margins expanded posteriorly, the lateral antennae are 4 times longer than wide, and the lateral antennal depressions diverge laterally such that the anterior region is shorter than the posterior one. The non-type specimen has a truncate interpalpal region, with its anterior margin slightly bilobed, and margins more or less parallel, the lateral antenna are more than 12 times longer than wide, and the lateral antennal depressions are barely distinct, visible only along the inner side of each antenna.

Remarks.

If these specimens are conspecific, the species would have a Gulf of México-Atlantic and Eastern Pacific distribution, which is untenable, for the following reasons. A strong genetic discontinuity between Gulf and Atlantic populations has been noted for specimens living in Florida ( Soltis et al. 2006, Bijak et al. 2018), and amphi-American species have been progressively recognized as including more than one distinct species upon morphological features and genetic markers combined ( Carrera-Parra and Salazar-Vallejo 2011), or even after the analysis of morphological differences ( Conde-Vela and Salazar-Vallejo 2015). Consequently, S. bassi should be regarded as a northwestern Atlantic species restricted to the Gulf of México; new names and descriptions will be provided for the specimens from Beaufort, NC, and Los Angeles, California in a subsequent publication. Chances are, however, that the same species might extend from the Gulf of México to Beaufort, NC On the other hand, it should be noted that specimens from San Francisco have been regarded as belonging to a different species since 2013 ( Norris 2013).

Figures

Figure 1. Sigambra bassi (Hartman, 1947) A holotype (LACM 142), anterior end, dorsal view B paratype (LACM 1549), anterior end, dorsal view C non-type specimen (LACM 6614), anterior end, dorsal view. Scale bars: 0.3 mm (A, C), 0.2 mm (B).