Sertularella diaphana ( Allman, 1885 )

Calder, Dale R., 2019, On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689 (1), pp. 1-141 : 89

Sertularella diaphana ( Allman, 1885)

Fig. 21i

Thuiaria distans Allman, 1877: 27 , pl. 17, figs. 1, 2 [not Sertularella distans ( Lamouroux, 1816) ].

Sertularella distans .— Nutting, 1904: 88.— Wallace, 1909: 137 [not Sertularella distans ( Lamouroux, 1816) ].

Thuiaria diaphana Allman, 1885: 145 , pl. 18, figs. 1–3.

Sertularella speciosa .— Fraser, 1943: 92.

Type locality. Australia: Queensland, Moreton Bay ( Allman 1885: 145, as Thuiaria diaphana ) .

Material examined. Southwest Florida Shelf, middle shelf west of North Naples, 26°16’15”N, 83°47’00”W, 76.2 m, 04 November 1980, on Nemertesia sinuosa , two juvenile colony fragments, 9 mm and 13 mm high, without gonophores, coll. Continental Shelf Associates, ROMIZ B4392.

Remarks. Sertularella diaphana ( Allman, 1885) has been collected most often in the western North Atlantic from offshore locations within the neritic zone, although exceptions occur. For example, Congdon (1907) found this species in shoal waters at the entrance of a cave in Castle Harbour, Bermuda. Its reported bathymetric distribution extends from shallow subtidal waters ( Allman, 1877, as Thuiaria pinnata ) to a depth of 1408 m ( Fernandez & Marques 2018). In the western Atlantic, it ranges from the Bermuda area (Calder 1990 [1991a], 2000) and from shelf waters off South Carolina ( Wenner et al. 1984, as Sertularella pinnigera ) to Brazil ( Oliveira et al. 2016). Records suggest that S. diaphana is widespread in the Caribbean region, and it is known as well from several locations in the Gulf of Mexico ( Calder & Cairns 2009; Castellanos et al. 2011; Mendoza-Becerril et al. 2018b). Elsewhere, it is believed to be essentially circumglobal in tropical and subtropical waters ( Millard 1975; Vervoort 1993; Schuchert 2003; Vervoort & Watson 2003; Galea 2010). With good reason, however, Galea noted the possibility that cryptic species exist among hydroids identified as S. diaphana , and DNA barcoding of geographically separated populations is needed to complement morphological accounts.

Only limited molecular data are available on hydroids of the speciose genus Sertularella Gray, 1848 , including S. diaphana . Based on current evidence, phylogenetic affinities of the species are somewhat unclear. Phylograms in Maronna et al. (2016) reveal that the species is quite divergent genetically from others of the genus included in the study, including the type species Sertularella polyzonias ( Linnaeus, 1758) . Their analysis was based on specimens of S. diaphana from Brazil. Again, additional molecular studies of this hydroid are warranted.

Gonophores in this species are liberated as medusoids from hydroids that appear to be dioecious (Gravier- Bonnet & Lebon 2002). Actively swimming gonophores were shed, one per gonotheca, early in the morning, and gametes were released over a life span of 2–3 hours.

The complex synonymy and nomenclature of S. diaphana , as presently understood, has been reviewed in works such as those of Calder (1990 [1991a]) and Vervoort (1993).

Reported distribution. Gulf coast of Florida. Dry Tortugas, shallow water ( Allman 1877: 27, as Thuiaria distans ).—North of Dry Tortugas, 25°04’30”N, 82°59’15”W, 26 ftm (48 m) ( Nutting 1904: 88, as Sertularella distans ).—Dry Tortugas ( Wallace 1909: 137, as Sertularella distans ).—Between Key West and Dry Tortugas, 24°24’N, 82°24’30”W, 34 ftm (62 m) ( Fraser 1943: 92, as Sertularella speciosa ).

Elsewhere in western North Atlantic. Bahamas: Cay Sal Bank, Double-Headed Shot Key (Cay), 3–4 ftm (5–7 m) ( Allman 1877: 278, as Thuiaria pinnata ).— Barbados: 56 ftm (102 m) ( Fewkes 1881a: 128, as Thuiaria pinnata ).— Bahamas: between Eleuthera and Little Cat islands, shallow water ( Nutting 1895: 224, as Thuiaria distans ).— Cuba: off Havana, 23°10’25”N, 82°20’24’”W, 33 ftm (60 m) ( Nutting 1904: 88, as Sertularella distans ).— Mexico: off Yucatan, near Arrowsmith Bank, 20°59’N, 86°23’W, 167 ftm (305 m) ( Nutting 1904: 88, as Sertularella distans ).— Bermuda: Castle Harbour, 32°20’30”N, 64°42’10”W, entrance of a cave ( Congdon 1907: 476, as Sertularella speciosa ).— Montserrat: off SW coast, 16°41’54”N, 62°13’24”W, 88 ftm (161 m) ( Fraser 1943: 92, as Sertularella speciosa ).— Puerto Rico: north coast, 18°30’30”N, 66°23’05”W, 40 ftm (73 m) ( Fraser 1944: 260, as Sertularella distans ).— Virgin Islands of the United States: St. John, south coast ( Vervoort 1968: 44, as Sertularella speciosa ).— Colombia: Santa Marta area ( Wedler 1975: 340, as Sertularella speciosa ).— Belize: Carrie Bow Cay ( Spracklin 1982: 246, as Sertularella speciosa ).— Dominican Republic: south coast ( Williams et al. 1983: 43, as Sertularella speciosa ).— Colombia: vicinity of Bahía de Cartagena, coastal areas, offshore islands ( Flórez González 1983: 121, as Sertularella speciosa ).— USA: South Carolina, inner (17–18 m) and middle (32–36 m) continental shelf + Georgia, middle continental shelf, 23–29 m ( Wenner et al. 1984: 21, 40, as Sertularella pinnigera ).— Puerto Rico: Mona Island + Desecheo Island ( Larson 1987: 514, as Sertularella speciosa ).— British Virgin Islands: Vir- gin Gorda ( Larson 1987: 514, as Sertularella speciosa ).— Colombia: Santa Marta area ( Bandel & Wedler 1987: 38, as Sertularella speciosa ).— Bermuda: Challenger Bank, 59 m, small colony on Aglaophenia rhynchocarpa (Calder 1990 [1991a]: 101).— Costa Rica: northern Punta Mona, Refugio Nacional de Vida Silvestre Gandoca- Manzanillo, 09°37’45”N, 82°37’07”W, 9 m ( Kelmo & Vargas 2002: 608).— Bermuda: Challenger Bank ( Calder 2000: 1134).— Mexico: Veracruz area, Arrecife La Blanquilla + Arrecife Anegada de Adentro ( Jones et al. 2008, as Sertularella speciosa ).—French Lesser Antilles: Guadeloupe, Grande-Terre, Grotte aux Barracudas, 16°27.343’N, 61°32.244’W, 21 m + Grande-Terre, Les Ancres, 16°27.002’N, 61°32.320’W, 15–18 m + Grande-Terre, L’Oeil, 16°26.782’N, 61°32.405’W, 12–17 m + Grande-Terre, Pointe d’Antigues, 16°26.251’N, 61°32.523’W + Grande- Terre, L’Avion, 16°25.610’N, 61°32.561’W, 15–25 m ( Galea 2010: 16, 17).— Cuba: Golfo de Batabanó, Boya El Límite, Punta Francés + Cayo Campos, Archipiélago de los Canarreos, reef (Castellanos et al. 2011: 23).—French Lesser Antilles: Les Saintes, Terre-de-Haut, Pointe à Cabrit, 15°52.645’N, 61°36.125’W, 10–15 m ( Galea 2010: 17).—French Lesser Antilles: Martinique, Le Prêcheur, Anse Céron, 14.837414°N, 61.223930°W ( Galea 2013: 17).—Caribbean Sea ( Wedler 2017b: 129, figs. 130–134).— Mexico: Alacranes Reef, on rocks ( Mendoza-Becerril et al. 2018b: 130).— Panama: Bocas del Toro area, the wall (25 m)/Pandora (20 m) ( Miglietta et al. 2018b: 108).

Figures

FIGURE 21. a, Amphisbetia distans: part of hydrocaulus with two hydrothecal pairs, Sanibel Island, ROMIZ B4387. Scale equals 0.1 mm. b, Amphisbetia distans: gonotheca, Sanibel Island, ROMIZ B4386. Scale equals 0.1 mm. c, Dynamena disticha: part of hydrocaulus with two hydrothecal pairs, Sanibel Island, ROMIZ B4410. Scale equals 0.1 mm. d, Dynamena pourtalesi: part of hydrocaulus with two hydrothecal pairs, Southwest Florida Shelf, ROMIZ B306. Scale equals 0.2 mm. e, Idiellana pristis: base of hydrocaulus with a branch, Sanibel Island, ROMIZ B4390. Scale equals 0.2 mm. f, Idiellana pristis: part of branch with hydrothecae, Sanibel Island, ROMIZ B4390. Scale equals 0.1 mm. g, Tridentata turbinata: part of hydrocaulus with two hydrothecal pairs, Sanibel Island, ROMIZ B4393. Scale equals 0.2 mm. h, Sertularella areyi: part of colony with two hydrothecae, Southwest Florida Shelf, ROMIZ B1978. Scale equals 0.2 mm. i, Sertularella diaphana: part of colony with three hydrothecae, Southwest Florida Shelf, ROMIZ B4392. Scale equals 0.2 mm. j, Sertularella unituba: part of colony with two hydrothecae, Southwest Florida Shelf, ROMIZ B2001. Scale equals 0.2 mm.