Plumularia strictocarpa Pictet, 1893

Calder, Dale R. & Faucci, Anuschka, 2021, Shallow water hydroids (Cnidaria, Hydrozoa) from the 2002 NOWRAMP cruise to the Northwestern Hawaiian Islands, Zootaxa 5085 (1), pp. 1-73 : 41

Plumularia strictocarpa Pictet, 1893

Fig. 11e, f

Plumularia strictocarpa Pictet, 1893: 55 , pl. 3 figs 47–49.— Coles et al., 2002a: 318; 2002b: 177, 234; 2004: 73; 2006: 492.— Carlton & Eldredge, 2009: 36.— Calder, 2020: 228, fig. 7h–j.

Plumularia setacea .— Cooke, 1977: 101, fig. 28.— Bailey-Brock, 1989: 591.— Carlton & Eldredge, 2009: 36 [not Plumularia setacea ( Linnaeus, 1758) ].

Type locality. Indonesia: Ambon Bay ; shallow water ( Pictet 1893) .

Voucher material. Midway Atoll, on rubble, 23.ix.2002, three colonies or colony fragments, to 1.3 cm high, with developing gonothecae, coll. A. Faucci, ROMIZ B5450 .— Laysan Island , 18.ix.2002, four colonies or colony fragments, to 2.5 cm high, without gonothecae, coll. A. Faucci, ROMIZ B5451 .— Laysan Island , on Halimeda sp. , 17.ix.2002, one colony, 2.5 cm high, without gonothecae, coll. A. Faucci, ROMIZ B5452 .— Kure Atoll , on Halimeda sp. , 25.ix.2002, three colonies or colony fragments, to 6 mm high, with gonothecae, coll. A. Faucci, ROMIZ B5453 .

Remarks. In terms of morphology, Plumularia strictocarpa Pictet, 1893 can be difficult to separate from P. setacea ( Linnaeus, 1758) , with the latter being taxonomically important as the type species of Plumularia Lamarck, 1816 ( International Commission on Zoological Nomenclature 1998, Opinion 1886). While colonies of P. strictocarpa are typically smaller and finer, the two species are most readily distinguished by their gonosomes. Fertile colonies from Kure and Midway atolls were therefore helpful in establishing identifications, with gonothecae of specimens examined here conforming with those of P. strictocarpa . Thus, they were typical of the species in being cocoon-shaped with spirally annulated walls ( Fig. 11f ), instead of being fusiform with a tubular neck and smooth walls, as in P. setacea . They also differed from gonothecae of the similar P. warreni Stechow, 1919b , which lack annulated walls ( Millard 1975). Notably, these three species fall within the same clade in DNA barcoding studies ( Moura et al. 2018), but were considered “likely good biological species” by Schuchert (2014).

Originally described from Ambon Bay, Indonesia ( Pictet 1893), P. strictocarpa has been widely reported across the tropical and subtropical Pacific Ocean. The species has been reported to be circumglobal in distribution ( Calder 2020), although evidence of genetic diversity now exists ( Schuchert 2014; Moura et al. 2018). Schuchert identified at least two and possibly three distinct lineages in specimens from locations in the Indian ( Mayotte, Maldives), Pacific ( French Polynesia), and Atlantic ( Brazil) oceans. Moura et al. concluded that these constitute three putative species.

Identifications from this study confirm the occurrence of P. strictocarpa in the Hawaiian region, and it is likely common in occurrence there.As implied earlier ( Calder 2020), reports of the temperate P. setacea from Hawaii have probably been based on misidentifications of P. strictocarpa .

Reported Distribution. Hawaiian archipelago. Oahu: Kaneohe Bay, on a variety of substrates ( Cooke 1977, as Plumularia setacea ); 2.4 km off SE coast, 20 m, on PVC settlement plates ( Bailey-Brock 1989, as P. setacea ); Kaneohe Bay, North Channel ( Coles et al. 2002a); Kaneohe Bay, Pristine Reef ( Coles et al. 2002a); Kaneohe Bay, “Floating City” ( Coles et al. 2002a); Kaneohe Bay, Moku Manu Island ( Coles et al. 2002a); Waikiki, Canoes, 3.5 m ( Coles et al. 2002b); Waikiki, Ala Wai buoy ( Coles et al. 2002b); Waikiki, Kaiser’s Channel ( Coles et al. 2002b); Hawaii Kai, Maunalua Bay, Channel Marker 1 ( Coles et al. 2002b); Hawaii Kai, Maunalua Bay, Koko Marina nearshore, 1.5 m ( Coles et al. 2002b); Palea Point, just outside Hanauma Bay, 8 m ( Calder 2020).—Maui, Maalaea Reef, near Maalaea Harbor ( Coles et al. 2004).—Island of Hawaii, Red Hill ( Coles et al. 2006).

Elsewhere. Reportedly circumglobal, tropical and subtropical waters ( Pictet 1893; Millard & Bouillon 1973; Hirohito 1974, 1995; Millard 1975; Ryland & Gibbons 1991; Migotto 1996; Calder 1997, 2013, 2020; Calder et al. 2003; Kirkendale & Calder 2003; Coles et al. 2003; Calder & Kirkendale 2005; Galea & Ferry 2015; Oliveira et al. 2016).

Figures

FIGURE 11. Plumulariidae. a, Monotheca flexuosa (Bale, 1894), part of hydrocaulus with two hydrocladia, each with a hydrotheca, Kure Atoll, ROMIZ B5447. Scale equals 0.1 mm. b, Monotheca gibbosa, sp. nov., holotype, part of hydrocaulus with hydrocladia and three hydrothecae, Laysan Island, ROMIZ B5448. Scale equals 0.1 mm. c, Monotheca gibbosa, sp. nov., holotype, part of hydrocaulus, and a hydrocladium with one hydrotheca, Laysan Island, ROMIZ B5448. Scale equals 0.05 mm. d, Plumularia floridana (Nutting 1900), part of hydrocaulus with bases of two hydrocladia, one with two hydrothecae, Gardner Pinnacles, ROMIZ B5449. Scale equals 0.1 mm. e, Plumularia strictocarpa Pictet, 1893, part of hydrocaulus with bases of two hydrocladia, one with two hydrothecae, Kure Atoll, ROMIZ B5453. Scale equals 0.1 mm. f, Plumularia strictocarpa Pictet, 1893, part of hydrorhiza, and proximal end of hydrocaulus with a gonotheca, Kure Atoll, ROMIZ B5453. Scale equals 0.2 mm.