Smittoidea spinigera ( Liu, 1990 )

López-Gappa, Juan, Liuzzi, María G., Castro, Karen L., Bobinac, Magalí & Schwindt, Evangelina, 2022, Fouling bryozoans in Argentine harbours (Southwest Atlantic): new records and the description of a new species, Zootaxa 5205 (4), pp. 374-400 : 389

Smittoidea spinigera ( Liu, 1990)

( Figs 30–32 )

Smittina spinigera Liu, 1990: 122 , fig. 2a–d.

Smittoidea spinigera : Liu, Yin & Ma 2001: 614, pl. 53, figs 1–3; McCuller & Carlton 2018: 155, fig. S23; Liuzzi et al. 2018: 218; Schwindt et al. 2020: 15.

Smittoidea sp. : Schwindt et al. 2014: Table S1 .

Material examined. MACN-In 43883, San Antonio Este harbour, October 10, 2005, collected by Evangelina Schwindt. MACN-In 43882, Ingeniero White harbour, June 22, 2016, collected by Sandra Fiori.

Description. Colony encrusting, unilaminar, multiserial, whitish.Autozooids subhexagonal, 232–368 × 171–277 µm, disposed quincuncially, separated by distinct sutures. Frontal shield convex, rugose, rising to a high peristome and a suboral avicularian umbo, with one series of 9–14 large marginal areolae separated by ridges. Primary orifice deep, obscured by the peristome, with 2–3 distal oral spines, only their bases persisting in ovicelled zooids; a pair of conspicuous, acute condyles pointing proximally and a lyrule ending laterally in two sharp points. Peristome with raised ridges and a proximal U-shaped sinus. A suboral avicularium directed proximally and obliquely upwards on the distal side of the umbo; rostrum blunt, crossbar complete, with a conspicuous ligula. A small rounded pore on each side of the suboral avicularium connects with the avicularian chamber. Ovicell hyperstomial, spherical, wider than long (144–175 × 166–198 µm), somewhat flattened frontally, not closed by the operculum, with a peripheral band of smooth ectooecium; entooecium pierced by 26–32 rounded or irregular pores with raised edges. Ancestrula tatiform, with proximal cryptocyst and nine delicate spines. Embryos orange.

Remarks. Several authors have recorded Smittoidea prolifica Osburn (see original description in Osburn 1952) as introduced in The Netherlands ( De Blauwe & Faasse 2004) and the German North Sea ( Markert et al. 2016; Kind & Kuhlenkamp 2018). Thanks to the courtesy of Hans De Blauwe, we were able to compare our material with SEM images of S. prolifica from the Netherlands. Our material differs from S. prolifica in the ligula of the suboral avicularium (present in S. spinigera , absent in S. prolifica ), in the orientation of the suboral avicularium (perpendicular to the frontal shield in S. prolifica , oblique in S. spinigera ), and also in the pores of the ovicell (with raised margins in S. spinigera , with smooth margins in S. prolifica ).

Smittoidea sp. of Schwindt et al. (2014) is the specimen of San Antonio Este stored at MACN-In 43883. Smittoidea spinigera was not found again at this harbour in 2018, whose pilings are now heavily populated by the introduced solitary ascidian Styela clava (Herdman) ( Pereyra et al. 2017; Castro et al. 2021).

Distribution. China ( Liu 1990; Liu et al. 2001 and references therein), Buenos Aires and Río Negro provinces (this study, and previous reports in Schwindt et al. 2014, 2020; Liuzzi et al. 2018). Although it was found on marine debris transported to the Hawaiian Islands and the NE Pacific by the 2011 tsunami that was generated by the Great East Japan Earthquake ( McCuller & Carlton 2018), this is the first record of S. spinigera established in coastal areas beyond its area of origin.

Figures

FIGURES 30–36. FIGURES 30–32. Smittoidea spinigera (MACN-In 43883); 30, general aspect; 31, ovicelled zooid; 32, close-up of primary orifice and suboral avicularium. FIGURES 33–36. Stephanollona boreopacifica (MACN-In 43884); 33, growing margin; 34, three zooids with oral spines; 35, ovicells and smaller oval avicularia; 36, close-up of larger triangular avicularia. Scale bars. 30, 33, 35, 36: 200 µm; 31, 34: 100 µm; 32: 50 µm.