Aglaophenia whiteleggei Bale, 1888

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 : 48-49

Aglaophenia whiteleggei Bale, 1888

Fig. 14d

Aglaophenia (?) whiteleggei Bale, 1888: 794 , pl. 21 fig. 8.

Type locality. Unknown ( Bale 1888); possibly Australia .

Voucher material. Pearl & Hermes Atoll, 28.ix.2002, two colonies, to 3.5 cm high, without corbulae, coll. A. Faucci, ROMIZ B5464 .— Midway Atoll, 23.ix.2002, one colony, 2 cm high, without corbulae, coll. A. Faucci, ROMIZ B5465 .— Kure Atoll , 25.ix.2002, one colony, 8 mm high, without corbulae, coll. A. Faucci, ROMIZ B5466 .— Laysan Island , detached, 17.ix.2002, one branched colony, 1.8 cm high, without corbulae, coll. A. Faucci, ROMIZ B5467 .

Remarks. The identity of Aglaophenia whiteleggei Bale, 1888 is somewhat in doubt. In describing this hydroid, Bale (1888) noted that the single, incomplete colony available to him was sterile, and its collection location was unknown (“ Hab.—?”). Subsequent reports of the species have been from Japan ( Stechow 1913b, 1923a; Jäderholm 1919; Stechow & Uchida 1931; Uchida 1958; Hirohito 1969; 1983; 1995), China ( Hargitt 1927, as Lytocarpus nuttingi ; Ling 1938, as L. nuttingi ; Wei 1959; Huang 1988; Xu et al. 2014b), South Korea ( Rho 1969; Rho & Park 1986), and Australia ( Watson 1994a, 2011b). As for Lytocarpus nuttingi Hargitt, 1927 , it has been included in the synonymy of A. whiteleggei by Huang (1988), Vervoort & Watson (2003), and Xu et al. (2014). Concurrently, it is accepted as a valid species ( Macrorhynchia nuttingi ) in WoRMS ( Schuchert 2021c).

Ensuing descriptions of the reproductive structures of A. whiteleggei differ significantly. For example, Stechow (1913b), Hargitt (1927, as Lytocarpus nuttingi ), Rho (1969) and Hirohito (1995) described them as forming an open corbula, as in certain species of Aglaophenia Lamouroux, 1812 . By contrast, Watson (2011b) considered them to be phylactogonia in her material, and she transferred the species to Macrorhynchia Kirchenpauer, 1872 . In her account, Watson neither cited records of the species from locations outside Australia nor mentioned any of the earlier accounts of the reproductive structures of A. whiteleggei . She thus considered her description to be the first account of them. Given material differences in these accounts, it appears certain that two different species have been reported under the binomen A. whiteleggei . To establish the likely identity of the species, and of specimens from the Northwestern Hawaiian Islands, accounts of the species by the various authors were compared here with the original description of Bale (1888).

In terms of cormidial structure, specimens from the Northwestern Hawaiian Islands corresponded quite closely with the accounts of Stechow (1913b), Ling (1938, as L. nuttingi ), Hirohito (1995), and particularly Jäderholm (1919). These all appear more like those described and illustrated by Bale (1888) than those of Watson (2011b), and are taken here to represent A. whiteleggei . As with those multiple accounts, the outline of the hydrothecal margin beyond the first pair of cusps is wavy to slightly crooked rather than distinctly cuspate, and the mesial nematotheca diverges at an angle from the axial line of the hydrotheca over its distal third rather than following it. Marginal cusps illustrated by Rho (1969) were as distinct as those in figures by Watson, but they differ in being pointed rather than blunt. While cormidia illustrated by Huang (1988) are close in morphology to those described here, the first pair of cusps were low, with the largest pair being located midway along the lateral sides of the rim. Mesial nematothecae were similar in shape, but were less divergent from the hydrothecae. The perisarc of the cormidia was illustrated as being more thickened, but the overall pattern of the internodal ridges was essentially identical. As with material examined here, the intrathecal ridge is shown to be incomplete by Bale (1888), Stechow (1913), Jäderholm (1919), Rho (1969), Huang (1988), and Hirohito (1995), but complete in Ling (1938), Wei (1959), and Watson (2011). However, that character may vary depending upon the age of the colony part examined. Otherwise, our cormidia are much as described by Bale, Stechow, Jäderholm, Ling, Wei, Huang, and Hirohito. Specimens examined here have therefore been assigned to A. whiteleggei . Nevertheless, the identity of the species warrants additional consideration.

Watson (1911) concluded from collection records in the Australian Museum, Sydney, and Museum Victoria, Melbourne, that the type material of Bale (1888) came from Port Jackson, Australia. Stranks (1993) had concluded that different material from an unknown locality might be the type. We simply follow Bale (1888) in concluding that the collection locality of A. whiteleggei is unknown.

Reported Distribution. Hawaiian archipelago. First record.

Elsewhere. Unknown location, possibly Australia ( Bale 1888); South Korea ( Rho 1969); Okinawa ( Yamada & Kubota 1987); Japan ( Hirohito 1995); China ( Huang 1988; Xu et al. 2014).

Figures

FIGURE 14. Aglaopheniidae. a, Aglaophenia postdentata Billard, 1913, part of a cladium with two hydrothecae, Gardner Pinnacles, ROMIZ B5462. Scale equals 0.1 mm. b, Aglaophenia suensonii Jäderholm, 1896, part of a cladium with three hydrothecae, Laysan Island, ROMIZ B5463. Scale equals 0.1 mm. c, Aglaophenia suensonii Jäderholm, 1896, corbula, Laysan Island, ROMIZ B5463. Scale equals 0.2 mm. d, Aglaophenia whiteleggei Bale, 1888, part of a cladium with two hydrothecae, Pearl & HermesAtoll, ROMIZ B5464. Scale equals 0.1 mm. e, Lytocarpia flexuosa (Lamouroux, 1816), part of a cladium with three hydrothecae, Pearl & Hermes Atoll, ROMIZ B5479. Scale equals 0.1 mm. f, Lytocarpia phyteuma (Stechow, 1919b), part of a cladium with two hydrothecae, Pearl & Hermes Atoll, ROMIZ B5468. Scale equals 0.1 mm. g, Macrorhynchia philippina Kirchenpauer, 1872, part of a cladium with two hydrothecae, Midway Atoll, ROMIZ B5470. Scale equals 0.1 mm. h, Macrorhynchia phoenicea (Busk, 1852), part of a cladium with three hydrothecae, Gardner Pinnacles, ROMIZ B5475. Scale equals 0.1 mm. i, Macrorhynchia phoenicea (Busk, 1852), one phylactocarp, without gonothecae, Gardner Pinnacles, ROMIZ B5475. Scale equals 0.2 mm.