Macrorhynchia allmani ( Nutting, 1900 )

Calder, Dale R., 2019, On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689 (1), pp. 1-141 : 97-98

Macrorhynchia allmani ( Nutting, 1900)

Fig. 22e

Aglaophenia ramosa Allman, 1877: 39 , pl. 23, figs. 1–4 [junior secondary homonym of Aglaophenia ramosa ( Busk, 1852) ; replaced before 1961 by a substitute name in current use (ICZN Art. 59.3)].

Aglaophenia allmani Nutting, 1900: 100 , pl. 22, figs. 2–3 [nomen novum for Aglaophenia ramosa Allman, 1877 ].— Van Gemerden-Hoogeveen, 1965: 78, fig. 43.

Aglaophenia (?) allmani .— Leloup, 1935a: 57 [part].

? Aglaophenia mercatoris Leloup, 1937: 113 , figs. 15A–D.

Type locality. USA: Florida, Florida Reef , 2–3 ftm (4–6 m) ( Allman 1877: 40, as Aglaophenia ramosa ) .

Material examined. Southwest Florida Shelf, middle shelf west of Gasparilla Island, 26°45.86’N, 83°21.44’W, 50 m, 18 July 1981, triangle dredge, one colony fragment, 5.6 cm high, without phylactocarps, coll. Continental Shelf Associates, ROMIZ B2187.

Remarks. The binomen Aglaophenia allmani was proposed by Nutting (1900) as a replacement name for A. ramosa Allman, 1877 , a junior secondary homonym of A. ramosa ( Busk, 1852) . The species is now assigned to Macrorhynchia Kirchenpauer, 1872 based on characters of both trophosome and gonosome, with the latter having recently been described by Galea (2013).An earlier account of the gonophores of Macrorhynchia allmani by Wedler (2004) has been discounted ( Calder 2013), having been based on a different species, likely M. furcata ( Nutting, 1900) .

As highlighted by Galea (2013), uncertainty has persisted in the formulation of taxonomically significant differences between M. allmani and several morphologically similar species ( Nematophorus grandis Clarke, 1879 , Pleurocarpa ramosa Fewkes, 1881 , Lytocarpus racemiferus Allman, 1883 , L. clarkei Nutting, 1900 , Aglaophenia mercatoris Leloup, 1937 , and A. longiramosa Fraser, 1945 ) from the warm western North Atlantic. Comparisons of some of these species have been reviewed in previous papers (Calder 1997, 2013; Galea 2013). Two of them from the Gulf coast of the United States ( A. mercatoris from near Tampa Bay; A. longiramosa from the coast of Alabama) were included by me (Calder 1997) as synonyms or questionable synonyms of M. allmani , although both have been provisionally recognized as valid by Galea (2013). Studies are needed to better establish relationships in this entire group of species.

Several records of M. allmani in the western North Atlantic that have been corrected or clarified in earlier work warrant review here. Congdon (1907) reported Lytocarpus philippinus (= Macrorhynchia philippina ) from Bermuda, but his illustration of it was based on M. allmani . Stechow (1920) recognized the error but compounded it by providing an unnecessary replacement name for the species ( M. bermudensis ). From current knowledge of the hydroids of Bermuda, it seems highly likely that Congdon combined two species under a single name, with specimens reportedly found along shallow shores indeed being M. philippina and the others (illustrated in fig. 37), from deeper waters on Challenger Bank, being M. allmani . Reports of M. clarkei from Challenger Bank ( Bennitt 1922, as Lytocarpus clarkei ) and from waters around Bermuda ( Calder 1986), a species not reliably known from the region, were almost certainly based on material of the abundant M. allmani (Calder 1997) . Van Gemerden-Hoogeveen (1965) discovered that material identified by Leloup (1935a) as Aglaophenia (?) allmani (= M. allmani ) from the Dry Tortugas, Florida, included two additional species, “ Aglaophenia elongata ” (actually A. dubia ) and “ Halicornaria hians var. balei ” (actually Gymnangium sinuosum ). Finally, as noted above, the hydroid from Colombia identified as M. allmani by Wedler (2004) appears to have been M. furcata ( Nutting, 1900) .

Macrorhynchia allmani is a robust species most often encountered in open coastal waters.

Reported distribution. Gulf coast of Florida. Florida Reef, 2–3 ftm (4–6 m) ( Allman 1877: 40, as Aglaophe- nia ramosa ).—Dry Tortugas, 27 ft (8 m) and 45 ftm (82 m) ( Leloup 1935a: 57, as Aglaophenia (?) allmani ; Van Gemerden-Hoogeveen 1965: 78, as as Aglaophenia allmani ).—?Off Tampa Bay, 7–10 miles (11–16 km) offshore, 8–10 ftm (15–18 m) ( Leloup 1937: 113, as Aglaophenia mercatoris ).

Elsewhere in western North Atlantic. St. Vincent: 95 ftm (174 m) ( Fewkes 1881a: 127, as Aglaophenia ramosa ; Fraser 1944: 366, as Aglaophenia allmani ).— Colombia: el Golfo de Darién, 09°30’N, 76°20’W, 42 ftm (77 m) ( Nutting 1900: 100, as Aglaophenia allmani ).— Bermuda: Challenger Bank ( Congdon 1907: 484 [part], as Lytocarpus philippinus ).— Barbados: 33 ftm (60 m) ( Nutting 1919: 100, as Aglaophenia allmani ).— Bermuda: Challenger Bank, 31–70 ftm (57–128 m) ( Bennitt 1922: 254, as Lytocarpus clarkei ).— Barbados: 100 ftm (183 m) ( Fraser 1943: 93, as Aglaophenia allmani ).— Virgin Islands of the United States: St. Croix, 17°37’55”N, 64°54’20”W, 115 ftm (210 m) ( Fraser 1943: 93, as Aglaophenia allmani ).— USA: Alabama, 29°58’N, 88°03’W, 16 ftm (29 m) ( Fraser 1945: 21, as Aglaophenia longiramosa ).— Aruba: 8 miles (13 km) SW of Sint Nicolaas Bay, 23–24 ftms (42–44 m) ( Fraser 1947b: 14, as Aglaophenia allmani ).— Virgin Islands of the United States: St. John, south coast ( Vervoort 1968: 68, as Aglaophenia (?) allmani ).— Virgin Islands of the United States: St. Thomas, Savannah Passage ( Vervoort 1968: 68, as Aglaophenia (?) allmani ).— USA: South Carolina, inner (17–18 m) and middle (32–36 m) continental shelf + Georgia, inner (17–22 m), middle (23–29 m) and outer (59–67 m) continental shelf ( Wenner et al. 1984: 21, 40, as Aglaophenia allmani ).— Bermuda: inshore and offshore waters ( Calder 1986: 139, as Macrorhynchia clarkei ).— Puerto Rico: Mona Island and Virgin Gorda Island ( Larson 1987: 20, as Aglaophenia allmani ).—? Colombia: Santa Marta area ( Bandel & Wedler 1987: 117, as Lytocarpus (Aglaophenia) allmani ).— Bermuda: 2.5 km SE of Castle Roads, 60–90 m + 1 km NE of Town Cut, 20 m + Challenger Bank, 60–70 m + 2 km S of St. David’s Lighthouse, 90 m + 2.5 km 2.5 km SSE of Castle Roads, 60 m (Calder 1997: 64, 65).— Bermuda: Challenger Bank + Argus (=Plantagenet) Bank ( Calder 2000: 1133).— Colombia: Golfo de Salamanca, 70 m + off Tolú, 70 m & 270 m + off Puerto Escondido, 70 m ( Posada et al. 2010: 79).— Cuba: Golfo de Batabanó ( Castellanos-Iglesias et al. 2011: 24).— USA: Florida, Bethel Shoal off Vero Beach, 27°42.6’N, 80°06.8’W, 24 m ( Calder 2013: 50).—French Lesser Antilles: Martinique, Le Prêcheur, 14.841853, -61.227858, 10–15 m + Le Diamant, 14.442310, -61.039697, 10–13 m ( Galea 2013: 41).—Caribbean Sea ( Wedler 2017b: 149, figs. 178A, B, 179, 180, 181A, B, 182).

Figures

FIGURE 22. a, Aglaophenia dubia: part of a hydrocladium with two hydrothecae, Southwest Florida Shelf, ROMIZ B2147. Scale equals 0.1 mm. b, Aglaophenia latecarinata: part of a hydrocladium with three hydrothecae, Fort Myers Beach, ROMIZ B4402. Scale equals 0.1 mm. c, Gymnangium sinuosum: part of a hydrocladium with one hydrotheca, Southwest Florida Shelf, ROMIZ B2203. Scale equals 0.1 mm. d, Lytocarpia tridentata: part of a hydrocladium with two hydrothecae, Florida Keys, Bahia Honda Channel, ROMIZ B3806. Scale equals 0.1 mm. e, Macrorhynchia allmani: part of a hydrocladium with two hydrothecae, Southwest Florida Shelf, ROMIZ B2187. Scale equals 0.1 mm. f, Macrorhynchia philippina: part of a hydrocladium with two hydrothecae, Sanibel Island, ROMIZ B4405. Scale equals 0.1 mm.