Hydroides cf. brachyacantha Rioja, 1941a

Bastida-Zavala, J. Rolando, McCANN, Linda D., Keppel, Erica & Ruiz, Gregory M., 2017, The fouling serpulids (Polychaeta: Serpulidae) from United States coastal waters: an overview, European Journal of Taxonomy 344, pp. 1-76 : 24-25

Hydroides cf. brachyacantha Rioja, 1941a

Figs 4B , 5

Hydroides cf. brachyacanthus – Bastida-Zavala & ten Hove 2002: 154 –155, figs 29A–K, 31A–D, 33 (Cura ҫao, Venezuela and Grenada; intertidal to 20 m, on Rhizophora and Thalassia , mud and sand, and a destroyer hull).

Hydroides brachyacantha (non Rioja 1941a) – Zibrowius 1970: 6 (São Sebastião, Ubatuba, Brazil; 6–15 m, rocks, corals and gorgonians). — Díaz-Díaz & Liñero-Arana 2001: 11 –12, fig. 2g–m (Cariaco Gulf, Venezuela; on PVC dock pilings).

Material examined

Seven specimens: BB (1) Aug. 2004, PB (6) Aug. 2002.

Diagnosis

Tube white; without peristomes, transverse ridges, longitudinal ridges or alveoli. Opercular peduncle smooth, white. Opercular funnel with 19–30 radii with pointed tip ( Fig. 4B ); verticil with 7–8 spines, strongly curving inwards; dorsalmost spine larger; all spines with basal internal spinule, without external and lateral spinules, or wings ( Fig. 4B ). Special collar chaetae with two blunt, short teeth and smooth distal blade.

Taxonomic remarks

The nominal species, Hydroides brachyacantha , has been recorded in various parts of the world including Australia ( Dew 1959; Straughan 1967; Kupriyanova et al. 2006), Hawaii ( Straughan 1969; Bailey-Brock 1976, 1987; Bastida-Zavala & ten Hove 2003; Carlton & Eldredge 2009), Palau and Yap Islands ( Imajima 1982), Truk and Ponape Islands, and Majuro Atoll ( Imajima & ten Hove 1984), Solomon Islands ( Imajima & ten Hove 1986), Israel ( Ben-Eliahu 1991; Ben-Eliahu & ten Hove 1992), northeastern Venezuela ( Díaz-Díaz & Liñero-Arana 2001) and Turkey ( Çinar 2006).

However, most of the records of H. brachyacantha from Australia belong to a new species recently described from Australia, H. amri Sun, Wong, ten Hove, Hutchings, Williamson & Kupriyanova, 2015 . The records from Hawaii also belong to a similar species, recently reported as H. cf. amri ( Bastida-Zavala et al. 2016) .The specimens recorded from Turkey apparently belong to H.brachyacantha sensu stricto, which might have reached the Turkish coast via ship-borne fouling ( Çinar 2006, fig. 2). Due to the absence of a holotype, a specimen collected from the type locality (Mazatlán, Mexico) was designated as the neotype ( Sun et al. 2016b).

While the specimens recorded from the western Atlantic also resemble H. brachyacantha , they do not have the characteristic large knobs on the verticil spines of the nominal species( Bastida-Zavala&ten Hove2003: figs 3A, C, G–K), nor the small “sharp to round knob” of H. amri ( Sun et al. 2015: fig. 3A–B).Apparently, in the Caribbean there are two forms of H. cf. brachyacantha , one from Grenada with a large dorsal spine and six smaller spines on the rest of the verticil ( Bastida-Zavala & ten Hove 2002: fig. 29A–C), and the other from Brazil and Venezuela, with dorsal spines smaller than those in Grenada’s specimens ( Bastida-Zavala & ten Hove 2002: fig. 29D–F). The specimens examined in this survey ( Fig. 4B ) are more similar to the Brazilian and Venezuelan form.

Ecology

Intertidal to sublittoral (20 m). In tropical marine areas, on mangrove, seagrass, rocks, corals and gorgonians, and artificial substrates ( Zibrowius 1970; Díaz-Díaz & Liñero-Arana 2001; Bastida-Zavala & ten Hove 2002).

Distribution

Eastern Caribbean to southeastern Brazil ( Zibrowius 1970; Bastida-Zavala & ten Hove 2002). In this work, Hydroides cf. brachyacantha was occasionally found on fouling plates from Biscayne Bay and Pensacola Bay, Florida ( Fig. 5 ). This species extends its northward range from Cura ҫao, southern Caribbean ( Bastida-Zavala & ten Hove 2002) to Pensacola Bay, Florida (2700 km).

Figures

Fig. 4. Serpulids from United States fouling plates. Hydroides bispinosa. A. Operculum, from Biscayne Bay, Florida (SERC-118756). – H. cf. brachyacantha. B. Operculum, Pensacola Bay, Florida (SERC- 92415). – H. dianthus. C. Operculum, Corpus Christi, Texas (SERC-87878RB). – H. dirampha. D. Operculum, Biscayne Bay, Florida (SERC-118709). – H. elegans. E. Operculum, San Diego, California (SERC-04075R). – H. floridana. F. Operculum, Corpus Christi, Texas (SERC-87968). – H. gracilis. G. Operculum, San Diego, California (SERC-34585R). – H. longispinosa. H. Operculum, Oahu, Hawaii (SERC-19654). – H. parva. I. Operculum, Biscayne Bay, Florida (SERC-118709). – H. sanctaecrucis. J. Operculum, Tampa Bay, Florida (SERC-66920R).

Fig. 5. Distribution of serpulids (Hydroides spp.) from United States fouling plates (closed symbols) and literature records (open symbols).