Amphisbetia distans ( Lamouroux, 1816 )

Castro Mendonça, Luana M., Parisotto Guimarães, Carmen R. & Haddad, Maria A., 2022, Taxonomy and diversity of hydroids (Cnidaria: Hydrozoa) of Sergipe, Northeast Brazil, Zoologia (e 21032) 39, pp. 1-65 : 49

Amphisbetia distans ( Lamouroux, 1816)

Fig. 21A

Synonyms available from: Peña Cantero and García Carracosa (2002) and Calder et al. (2019).

Dynamena distans Lamouroux 1816: 180 , pl. 5, fig. 1A, B.

Sertularia erasmoi Vannucci Mendes 1946 , – Vannucci, 1949, 1951a [polyp].

Sertularia minuscula Vannucci, 1949 , 1950, 1951a [polyp].

Tridentata distans – Calder and Maÿal, 1998, – Grohmann, 2006 [polyp].

Description: Colonies erect, up to 11.4 mm high, with several pairs of hydrothecae, arising from a creeping hydrorhiza. Stem monosiphonic, unbranched, basal part ahydrothecate separated by an oblique node. The remaining part of the stem composed of several internodes separated by transverse and oblique nodes, each one with a pair of opposite hydrothecae. Hydrothecae tubular, 0.18–0.22 mm long, increasing in diameter distally, 0.76–0.96 mm maximum diameter, adnate to stem for up to half its high, free distal portion inclined outwards. The adnate portion of the paired hydrothecae in contact. The basal portion of hydrothecae with one or two internal projections. Margin smooth, with two abcauline triangular cusps and a small- er adcauline one. The operculum is composed of two valves, the adcauline usually divided in half. Gonothecae ovoid, 0.73–0.80 mm high, 0.45–0.51 mm wide, circular opening, arising in short pedicel in one of the basal internodes. Nematocysts, probably microbasic mastigophores discharged in coenosarc and hydranth (11.6–13.1 × 3.4–3.9 µm).

Material examined: PCS – abundant colonies, several of them with gonothecae, from the dry and rainy seasons; VB – two infertile colonies, one from dry and the other from rainy season. CZUFS CNI-00025; CNI-00061; CNI-00203; CNI-00204; CNI-00206.

Stations: PCS – 1, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17, 18; VB – C1P56, C2P34.

Bottom: gravel, sand, and mud.

Distribution: Brazil – Fernando de Noronha ( Pires et al. 1992, Amaral et al. 2009), Ceará ( Marques et al. 2006, Shimabukuro 2007), Paraíba (Felipe F. Campos unpub. data), Pernambuco ( Calder and Maÿal 1998), Alagoas (Maximiliano M. Maronna unpub. data), Bahia ( Grohmann et al. 2003), Espírito Santo ( Vannucci 1949, 1951a, Grohmann et al. 1997, 2003), Rio de Janeiro ( Vannucci 1949, 1950, 1951a, Nogueira et al. 1997, Miranda et al. 2015), São Paulo ( Vannucci Mendes 1946, Vannucci 1949, 1951a, Migotto 1996, Oliveira et al. 2006, Shimabukuro 2007, Oliveira and Marques 2011, Silveira and Morandini 2011, Miranda et al. 2015), Paraná ( Miranda et al. 2015, Maria A. Haddad unpub. data), and Santa Catarina ( Miranda et al. 2011, 2015, Bouzon et al. 2012). World distribution – circumglobal or likely circuntropical ( Calder 1991, Boero and Bouillon 1993, see detailed records in Peña Cantero and García Carrascosa 2002).

Taxonomic remarks: The species has been recorded as Sertularia distans and Tridentata distans in Brazil until the molecular results presented by Moura et al. (2011) and Maronna et al. (2016) resulted in the referral of the species to Amphisbetia (new combination by Calder 2019).

Remarks: PCS colonies colonizing algae, Bryozoa, and Thyroscyphus ramosus . The colonies from Vaza-Barris were on Pennaria disticha .

Figures

Figure 21. (A) Amphisbetia distans: detail of a stem with few hydrothecae and one gonotheca; (B-C) Diphasia digitalis: (B) general view of a stem; (C) detail of two pairs of hydrothecae; (D) Dynamena disticha: detail of a stem with two pairs of hydrothecae and one gonotheca; (E, G-H) Idiellana pristis: (E) detail of the hydrocladium with three pairs of hydrothecae; (G) detail of a stem with few gonothecae (red arrows); (H) detail of two gonothecae; (F) Diphasia tropica: detail of a stem with three pairs of hydrothecae; (I) Dynamena crisioides: detail of a stem with few hydrothecae.