Thyroscyphus ramosus Allman, 1877

Calder, Dale R., 2019, On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689 (1), pp. 1-141 : 76-77

Thyroscyphus ramosus Allman, 1877

Figs. 19k, l

Thyroscyphus ramosus Allman, 1877: 11 , pl. 6, figs. 5, 6.— Wallace, 1909: 137.— Splettstösser, 1929: 55.— Fraser, 1943: 91.— Van Gemerden-Hoogeveen, 1965: 15.

Type locality. USA: Florida, south of Sand Key , 10 fathoms (18 m) ( Allman 1877: 11) .

Material examined. Sanibel Island, beach at Lighthouse Point, 26°26’57”N, 82°01’07”W, detached, in intertidal pools, 03 August 2014, one colony fragment, 2.1 cm high, without gonophores, coll. D. Calder, ROMIZ B4385.

Remarks. Thyroscyphus ramosus Allman, 1877 is another species originally described from collections made in the Straits of Florida by L.F. de Pourtalès. While its colony form resembles that of T. marginatus ( Allman, 1877) , hydrothecae of the two species are quite different. In T. ramosus , the hydrothecal margin is quadricuspate and bears an operculum of four valves, while in T. marginatus it is entire and open, with the operculum having been shed. Thyroscyphus longicaulis Splettstösser, 1929 from the Caribbean Sea resembles T. ramosus , but its hydrothecae are longer and more slender, marginal cusps are more deeply incised, and a somewhat more developed pedicel is present ( Vervoort 1968). Also similar is T. fruticosus ( Esper, 1791 [1793]) from the Indo-Pacific region. Its marginal cusps appear to be shallower than those of T. ramosus , and its pedicels are even less well developed.

As with T. marginatus , T. ramosus is predominantly a hydroid of warm and shallow waters. Of the two species, T. ramosus has been reported less frequently and its distribution is more limited. It has not been reported in the northern Gulf of Mexico and does not occur as far north on the American Atlantic coast. The known range in the Americas currently extends from the continental shelf off South Carolina ( Wenner et al. 1984) to Brazil ( Oliveira 2016). An amphi-Atlantic species, it has also been reported from Freetown, Sierra Leone, in the tropical eastern Atlantic ( Vervoort 1959). A record from the Gulf of Mannar in the Indian Ocean by Leloup (1932) seems questionable.

Other detailed accounts of T. ramosus include those of Splettstösser (1929), Fraser (1944), Vervoort (1968), Migotto (1996), Shimabukuro & Marques (2006), Galea (2008), and Calder (2013).

Reported distribution. Gulf coast of Florida. South of Sand Key, 10 fathoms (18 m) ( Allman 1877: 11).—Dry Tortugas ( Wallace 1909: 137; Splettstösser 1929: 55; Van Gemerden-Hoogeveen 1965: 15).—Inside Florida Reef, 4 ftm (7 m) ( Fraser 1943: 91).

Elsewhere in western North Atlantic. Cuba: off Morro Castle, 100–250 ftm (183–457 m) ( Nutting 1895: 87).– Venezuela: near Los Testigos Islands, 11 m ( Versluys 1899: 31).— Saint-Barthélemy: 2 ftm (4 m) ( Jäderholm 1903: 273).— Haiti: Port du Paix ( Splettstösser 1929: 55).— Virgin Islands of the United States: St. John, “Loango Westindien” (=Lovango Cay) ( Splettstösser 1929: 55).— Bahamas: off Orange Key, 9 ftm (16 m) ( Fraser 1943: 91).— Trinidad: Maguaripe Bay (=Macqueripe Bay) ( Fraser 1943: 91).— Anguilla: off Sombrero, 240 ftm (439 m) ( Fraser 1943: 91).— Puerto Rico: north coast, 18°30’30”N, 66°23’05”W, 40 ftm (73 m) ( Fraser 1944: 183).— Puerto Rico: off Culebra Island, 18°19’10”N, 65°19’40”W, 10 ftm (18 m) ( Fraser 1944: 183).— St. Eustatius: Oranjestad, near Billy Gut, tidal zone ( Van Gemerden-Hoogeveen 1965: 15).— Colombia: widespread ( Van Gemerden-Hoogeveen 1965: 15; Wedler 1975: 340; Flórez González 1983: 123; Bandel and Wedler 1987: 41).— Haiti: St. Marc ( Vervoort 1968: 33).— Barbados ( Vervoort 1968: 33).— Venezuela: La Guaira ( Vervoort 1968: 33).— Virgin Islands of the United States: St. Thomas, sound + Savannah Passage ( Vervoort 1968: 33).— Virgin Islands of the United States: St. John, south coast ( Vervoort 1968: 33).— USA: Florida, Indian River region, Sebastian Inlet + Fort Pierce breakwater ( Winston 1982: 164, 165; 2009: 231).— USA: South Carolina, middle continental shelf E of Cape Island, 32–36 m ( Wenner et al. 1984: 40).— Puerto Rico: Mona Island and Desecheo Island ( Larson 1987: 514).— Colombia: Bahía de Chengue, on Rhizophora ( Reyes & Campos 1992: 108) .— Costa Rica: near Limón, 9–20 m ( Kelmo & Vargas 2002: 606).— Panama: Bocas del Toro, Swan’s Key, 09°27’12.2”N, 82°18’01.8”W, 1–4 m + Boca del Drago, 0–3 m + Drago 2, 2– 4 m ( Calder & Kirkendale 2005: 484).—French Lesser Antilles: Les Saintes, Terre-de-Haut, Pain de Sucre, 15°51’45”N, 61°35’60”W, rocky shore ( Galea 2008: 39).— Mexico: Campeche ( López Garrido 2008: 168).—French Lesser Antilles: Guadeloupe, Grande-Terre, Les Ancres, 16°27.002’N, 61°32.320’W, 15–18 m + L’Oeil, 16°26.782’N, 61°32.405’W, 12–17 m + Pointe d’Antigues, 16°26.251’N, 61°32.523’W ( Galea 2010: 4).— Cuba: Golfo de Batabanó ( Castellanos-Iglesias et al. 2011: 20).—French Lesser Antilles: Martinique ( Galea 2013: 50).— USA: Florida, off Fort Pierce, 27°29.6’N, 80°17.0’W, 7–8 m + Fort Pierce Inlet, north jetty ( Calder 2013: 24).—Caribbean Sea ( Wedler 2017b: 138, figs. 152–155A, B, 156).— Panama: Bocas del Toro area, Swan’s Cay ( Miglietta et al. 2018b: 108).

Figures

FIGURE 19. a, Halecium lightbourni: part of hydrocaulus with hydrothecae, Fort Myers Beach, ROMIZ B4377. Scale equals 0.1 mm. b, Halecium nanum: stolon with hydrocaulus and two hydrothecae, Sanibel Island, ROMIZ B4378. Scale equals 0.05 mm. c, Halecium tenellum: part of colony with a hydrotheca, Southwest Florida Shelf, ROMIZ B4379. Scale equals 0.05 mm. d, Halecium tenellum: part of colony with renovated hydrothecae, Southwest Florida Shelf, ROMIZ B4379. Scale equals 0.2 mm. e, Halecium sp.: part of a branch with three hydrothecae, Sanibel Island, ROMIZ B4381. Scale equals 0.1 mm. f, Halecium sp.: part of a branch with a hydrotheca, Southwest Florida Shelf, ROMIZ B1594. Scale equals 0.1 mm. g, Nemalecium lighti: part of colony with five hydrothecae, Fort Myers Beach, ROMIZ B4419. Scale equals 0.2 mm. h, Nemalecium lighti: two internodes, with hydrothecae, Fort Myers Beach, ROMIZ B4419. Scale equals 0.1 mm. i, Thyroscyphus marginatus: part of colony with three hydrothecae, Sanibel Island, ROMIZ B4382. Scale equals 0.5 mm. j, Thyroscyphus marginatus: hydrotheca, Sanibel Island, ROMIZ B4382. Scale equals 0.2 mm. k, Thyroscyphus ramosus: part of colony with three hydrothecae, Sanibel Island, ROMIZ B4385. Scale equals 0.5 mm. l, Thyroscyphus ramosus: hydrotheca, Sanibel Island, ROMIZ B4385. Scale equals 0.2 mm.