Monostaechas quadridens

Monostaechas quadridens (McCrady, 1859)

Fig. 23g

Plumularia quadridens McCrady, 1859: 199.—A. Agassiz, 1865: 140.

Monostaechas ? quadrideus.— Wallace, 1909: 137 [incorrect subsequent spelling].

Monostaechas quadridens.— Leloup, 1937: 108, fig. 10A.— Fraser, 1943: 95.— Vervoort, 1968: 61, figs. 28a, b.

Type locality. USA: South Carolina, Charleston (McCrady 1959: 199).

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, 4.3 cm high, without gonophores, coll. Continental Shelf Associates, ROMIZ B2100.— Sanibel Island, beach at Lighthouse Point, 26°26’58”N, 82°01’04.5”W, on stranded Sargassum pteropleuron, 21 March 2018, 22° C, 34.5‰, one colony, 7 mm high, without gonophores, coll. D. Calder, ROMIZ B4401.

Remarks. The reported range of Monostaechas quadridens in the western Atlantic is from southern New England (Nutting 1900, 1901) to northern Argentina (Oliveira et al. 2016), including the Gulf of Mexico (Deevey 1950, 1954; Calder & Cairns 2009). It is particularly common in the southeastern United States on reefs and banks of the continental shelf. Reports of the species from shallow inshore waters in the region have usually been of detached colonies (McCrady 1859; Calder 1983) that were probably carried landwards into estuarine areas by water currents. Based on its known distribution, this hydroid is considered here to be a warm-temperate to tropical species, usually found at moderate depths within the neritic zone. Current records suggest that M. quadridens is circumglobal (Schuchert 1997), but its occurrence beyond the Atlantic Ocean needs confirmation.

Shuchert (1997) discovered that hydroids from the Bahamas, identified as Antennella diaphana diaphana by Van Gemerden-Hoogeveen (1965), were referable to this species. His account of M. quadridens, and that of Ansín Agís et al. (2001), provide further discussion, illustrations, and synonymy lists of the species. Monostaechas dichotoma Allman, 1877 from off Pacific Reef in the Straits of Florida is considered a synonym (e.g., Nutting 1900; Fraser 1944; Vervoort 1968; Schuchert 1997; Ansín Agís et al. 2001).

Reported distribution. Gulf coast of Florida. Florida Ship Channel (A. Agassiz 1865: 140, as Plumularia quadridens).—Florida Reef (A. Agassiz 1865: 223, as Plumularia quadridens).—Dry Tortugas (Wallace 1909: 137, as Monostaechas ? quadrideus “or some related species”).—Off Tampa Bay, 7–10 miles (11–16 km) offshore, 8–10 ftm (15–18 m) (Leloup 1937: 108).—Off Dry Tortugas, 24°36’40”N, 83°02’20”W, 16 ftm (29 m) (Fraser 1943: 95).—Dry Tortugas, Bird Key reef + SW Channel, 10–12 ftm (18–22 m) (Vervoort 1968: 61).

Elsewhere in western North Atlantic. USA: South Carolina, Charleston, floating in water (McCrady 1859: 199, as Plumularia quadridens).— USA: Florida, off Pacific Reef, 283 ftm (518 m) (Allman 1877: 37, as Monostaechas dichotoma).— Mexico: Yucatan Bank, 50 ftm (91 m) (Fewkes 1881a: 128, as Monostaechas dichotoma).— Barbados: 76 ftm (139 m) (Nutting 1900: 76).— USA: Massachusetts, near Martha’s Vineyard, 22 ftm (40 m) (Nutting 1900: 76; 1901: 365).—West Indies (Nutting 1901: 365).— USA: North Carolina, near Beaufort (Fraser 1912b: 380).— USA: Florida, east coast, 15–20 miles (24–32 km) offshore, 20–30 ftm (32–48 m) (Leloup 1937: 108, as Monostaechas quadridens forme fisheri).— Barbados: 100 ftm (183 m) (Fraser 1943: 95).— USA: South Carolina, Charleston, off the bar (Fraser 1943: 95).— USA, North Carolina, off Cape Hatteras, 14 ftm (26 m) (Fraser 1944: 335).— USA: South Carolina, Blackfish Bank (Fraser 1945: 21).— USA: Texas, Port Isabel, on Podochela sidneyi (Deevey 1950: 347).— USA: North and South Carolina, reefs on continental shelf (Pearse & Willams 1951: 136).— Bahamas: New Providence (Van Gemerden-Hoogeveen 1965: 49, as Antennella diaphana diaphana (part); Schuchert 1997: 130).— Virgin Islands of the United States: St. Thomas, Savannah Passage + Sound + south coast (Vervoort 1968: 62).— USA: North Carolina, Lithothamnion reef S of Cape Lookout (Cain 1972: 80).—? USA: Texas, West Flower Garden Bank, 156 ft (48 m) (Defenbaugh 1974: 101, as Monostaechas sp.).— USA: South Carolina, Port Royal Sound, Chechessee River, 32°17’30”N, 80°45’00”W, 9 m, unattached (Calder & Hester 1978: 91; Calder 1983: 17).— Belize: Carrie Bow Cay (Spracklin 1982: 246).— USA: South Carolina, ledges, inner continental shelf (Calder 1983: 18).— USA: South Atlantic Bight, between South Carolina and northern Florida (Wenner et al. 1983: 148).— Colombia: Bahía de Cartagena (Flórez González 1983: 123).— USA: South Carolina, inner (17–18 m), middle (32–36 m) and outer (46–69 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).– USA: Texas, shelf edge banks (Rezak et al. 1985: 224).— USA: South Carolina, continental shelf, fouling plates (Van Dolah et al. 1988: 694).— USA: South Carolina and Georgia, inner continental shelf, on artificial reefs (Wendt et al. 1989: 1112).— USA: South Carolina, coastal areas, in stomachs of Atlantic spadefish (Hayse 1990: 81).— Belize: South Water Cay, on Thalassia (Kaehler & Hughes 1992: 331).— USA: Florida, St. Lucie Inlet, 27°10.8’N, 80°00.8’W, 44 m (Schuchert 1997: 130; Calder 2013: 45).— USA: South Carolina, inner continental shelf SE of Charleston, 32°30.0’N, 79°42.3’W, 18 m (Schuchert 1997: 130).— Bahamas: New Providence (Schuchert 1997: 130).— Bermuda:Argus (=Plantagenet) Bank (Calder 2000: 1135).—French Lesser Antilles: Guadeloupe, Grande-Terre, Pointe Plate, 16°27.220’N, 61°32.128’W, 15–20 m (Galea 2010: 26).— Cuba: Punta Francés, Boya 56 (Castellanos et al. 2009: 96, 2011: 18).—French Lesser Antilles: Martinique (Galea 2013: 50).— Mexico: Alacranes Reef, on sponges, corals, rocks (Mendoza-Becerril et al. 2018b: 130).