Pennaria disticha Goldfuss, 1820

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 : 7-8

Pennaria disticha Goldfuss, 1820

Fig. 2a

Pennaria disticha Goldfuss, 1820: 89 .— Hoover, 1998: 20, unnumbered figure; 2006: 20, unnumbered figure.— Coles et al., 2002a: 318, 343; 2002b: 21, 25, 32; 2004: 22, 73; 2006: 489, 492, 494; 2009: 59, 69, 76, 82.— DeFelice et al., 2001: 15, two unnumbered photographs; 2002: 25, 50.— Godwin et al. 2006: 27.— See et al., 2009: 276, 281.— Calder, 2010: 63, fig. 43.— Miglietta et al., 2015: 5; 2019: 86, 87.

Pennaria sp. — Edmondson, 1933: 23, figs 11, 12a; 1946: 24, figs 12, 13a.

Corydendrium splendidum Boone, 1938: 33 , pl. 4.

Pennaria tiarella .— Edmondson & Ingram, 1939: 256.— Chu & Cutress, 1954: 9.— Josephson, 1961: 565.— Pardy & Lenhoff, 1968: 197, figs 1–3.— Banner, 1968: 21.— Mariscal & Lenhoff, 1969: 330.— Rees et al., 1970: 309, figs 1, 2.— Reed, 1971: 48.— Pardy, 1971: 84, figs 1–3.— Rees, 1971: 119, figs 1, 2.— Long, 1974: 27.

Halocordyle disticha .— Cooke, 1977: 80, fig. 8.— Coles et al., 1999a: 194, 205, 209; 1999b: 150.

Pennaria distachia .— Menza & Monaco, 2009: 1 [incorrect subsequent spelling].

Type locality. Italy: Gulf of Naples (see Calder 2013: 7) .

Voucher material. Pearl & Hermes Atoll , 19.ix.2002, one colony fragment, 6 mm high, with a medusa bud, coll. A. Faucci, ROMIZ B5404 .— French Frigate Shoals, 11.ix.2002, four colonies or colony fragments, to 10 cm high, with medusa buds, coll. A. Faucci, ROMIZ B5488 .

Remarks. Pennaria disticha Goldfuss, 1820 has been reported numerous times from shallow tropical and temperate waters worldwide, although cryptic species seem certain to exist under the name ( Miglietta et al. 2015, 2019). A taxonomic overview of the species in the Hawaiian Islands has been given earlier ( Calder 2010).

The earliest record of P. disticha from Hawaii is based on Boone (1938, as Corydendrium splendidum ), whose material was collected in Kaneohe Bay during 1928. It is now the most frequently reported hydroid species across the Hawaiian archipelago. DeFelice et al. (2001) noted that P. disticha is common as a fouling organism in harbours of the main islands, as well as in cracks, crevices, and protected areas of reefs. In the Northwestern Hawaiian Islands, it has been reported to date from Necker Island, French Frigate Shoals, Gardner Pinnacles, Maro Reef, Laysan Island, Lisianski Island, Pearl & Hermes Reef, Midway Atoll, and Kure Atoll ( See et al. 2009). A record of its occurrence at Midway Atoll ( Carlton & Eldredge 2009), based on DeFelice et al. (1998), could not be confirmed, although it has been reported from there by Godwin et al. (2006) and See et al. (2009).

Contemporary taxonomic accounts of Pennaria disticha are given in works by Calder (1988a, as Halocordyle disticha, 2010 , 2013, 2019) and Schuchert (2006). DeFelice et al. (2001) reported that hydroid populations of the species in Hawaii are capable of inflicting a mild sting.

Reported Distribution. Hawaiian archipelago. Oahu: Kaneohe Bay ( Edmondson 1933, 1935, as Pennaria tiarella ; Boone 1938, as Corydendrium splendidum ; Edmondson & Ingram 1939, as “probably Pennaria tiarella ”; Josephson 1961, as P. tiarella ; Banner 1968, as P. tiarella ; Pardy & Lenhoff 1968, as P. tiarella ; Mariscal & Lenhoff 1969, as P. tiarella ; Rees et al. 1970, as P. tiarella ; Pardy 1971, as P. tiarella ; Rees 1971, as P. tiarella ; Reed 1971, as P. tiarella ; Coles et al. 2002a; Calder 2010; Miglietta et al. 2015, 2019); Pearl Harbor ( Edmondson 1933, as Pennaria sp. ; Long 1974, as P. tiarella ; Cooke 1977, as Halocordyle disticha ; Hoover 1998, 2006; Coles et al. 1999b, as H. disticha ; Coles et al. 2009; Calder 2010; Miglietta et al. 2015, 2019); Ala Wai Harbor ( Cooke 1977, as H. disticha ; Coles et al. 1999a, as H. disticha ; Calder 2010); Kewalo Basin ( Cooke 1977, as H. disticha ; Coles et al. 1999a, as H. disticha ; Calder 2010; Miglietta et al. 2015, 2019); Honolulu Harbor ( Cooke 1977, as H. disticha ; Coles et al. 1999a, as H. disticha, 2009 ; Calder 2010); Lanai Lookout ( Hoover 1998, 2006); Pearl Harbor ( Coles et al. 1999b; Calder 2010; Miglietta et al. 2019); Waikiki ( Coles et al. 2002b); Maunalua Bay ( Coles et al. 2002b); Kuapâ Pond ( Coles et al. 2002b); Keehi Lagoon/ Marina ( Coles 2009; Miglietta et al. 2015, 2019); Haleiwa ( Miglietta et al. 2015, 2019).—French Frigate Shoals ( DeFelice et al. 2002; Godwin et al. 2006; See et al. 2009).—Kauai: Nawiliwili Harbor Pier 2 ( Coles et al. 2004); Marriott Hotel Reef ( Coles et al. 2004, 2006); Port Allen Harbor Main Pier ( Coles et al. 2004); Port Allen Reef ( Coles et al. 2004); Port Allen Harbor ( Coles et al. 2006); Hoai Bay ( Coles et al. 2006).—Molokai: Hale O Lono Harbor Dock ( Coles et al. 2004); Kaunakakai Dock ( Coles et al. 2004).—Maui: Kahului Harbor Pier 1 ( Coles et al. 2004); Kahului Harbor Pier 2 ( Coles et al. 2004); Maalaea Small Boat Harbor ( Coles et al. 2004); Mala Wharf ( Coles et al. 2006); Maui ( Miglietta et al. 2015, 2019).—Island of Hawaii: Kawaihae Reef ( Coles et al. 2004, 2006); Kawaihae Harbor Main Pier ( Coles et al. 2004); Hilo Harbor Pier 1 ( Coles et al. 2004).—All of the main islands ( DeFelice et al. 2001; Carlton & Eldredge 2009).—Laysan Island ( Godwin et al. 2006; See et al. 2009).—Lisianski Island ( Godwin et al. 2006; See et al. 2009; Calder 2010; Miglietta et al. 2015, 2019).—Pearl & Hermes Atoll ( Godwin et al. 2006; See et al. 2009; Calder 2010; Miglietta et al. 2015, 2019).— Kure Atoll ( Godwin et al. 2006; See et al. 2009).— Midway Atoll ( Godwin et al. 2006; See et al. 2009).—Necker Island ( See et al. 2009).—Gardner Pinnacles ( See et al. 2009).—Maro Reef ( See et al. 2009).—Northwestern Hawaiian Islands ( Menza & Monaco 2009, as Pennaria distachia ).

Elsewhere. Considered circumglobal in tropical and warm-temperate waters ( Calder 2010), although cryptic species likely exist ( Miglietta et al. 2015, 2019).

Figures

FIGURE 2. Pennariidae, Oceaniidae, Eudendriidae, and Phialellidae. a, Pennaria disticha Goldfuss, 1820, hydranth with a medusa bud and part of pedicel, Pearl & Hermes Atoll, ROMIZ B5404. Scale equals 0.2 mm. b, Turritopsis sp., hydrocaulus with two hydranths, Midway Atoll, ROMIZ B5490. Scale equals 0.2 mm. c, Eudendrium merulum Watson, 1985, hydranth and part of pedicel, Nihoa, ROMIZ B5405. Scale equals 0.1 mm. d, Eudendrium merulum Watson, 1985, hydrocaulus and proximal ends of three branches, Nihoa, ROMIZ B5405. Scale equals 0.2 mm. e, Eudendrium merulum Watson, 1985, female gonophores, Nihoa Island, ROMIZ B5405. Scale equals 0.1 mm. f. Phialellidae (undetermined), three hydrothecae, Gardner Pinnacles, ROMIZ B5406. Scales equal 0.05 mm.