Beroe pseudocucumis, Shiganova & Abyzova, 2022

Shiganova, Tamara A. & Abyzova, Galina A., 2022, Revision of Beroidae (Ctenophora) in the southern seas of Europe: systematics and distribution based on genetics and morphology, Zoological Journal of the Linnean Society 194, pp. 297-322 : 306-307

BEROE PSEUDOCUCUMIS SP. NOV.

Zoobank registration: urn:lsid:zoobank.org:act:87D103FA-F278-4D2F-B206-0AAF96632F0C

Synonyms: Beroe ovata of Eschscholtz, 1829);

Beroe cucumis sensu Mayer (of Bayha et al., 2004)

Etymology: From Latin cucumis , cucumber, and the Greek prefix ψευδο-, false, because the name B. cucumis had been misapplied to this species in the past.

The body is long-oval, from slightly flattened to nearly circular in cross-section, l/w: 2.0–3.0, with length up to three times longer than the width, which is specific for this species. The aboral end and oral part is rounded, which is specific for this species ( Fig. 5 ). Adult length varies from 50 to 160 mm. The eight meridional canals lie under eight rows of ciliary combs, which extend for three-quarters of the length from aboral pole towards the mouth or, sometimes, further ( Fig. 5A, B ). Lateral branches of the meridional canals (diverticulae) are dense (which is unique in this species) and do not anastomose with each other ( Fig. 5C ). Stomodaeum is voluminous and occupies most of the body (four-fifths). The colour is pink or translucent, being slightly pink along the ciliary comb rows. There is an axial funnel tube; the aboral pole is fringed with a row of long, branched papillae, which is also specific for this species ( Fig. 5D ).

This new species differs from Beroe cucumis by its long body (up to three times longer compared to width), the roundish shape of the mouth, the dense diverticulae that do not anastomose with each other. Its stomodaeum is large and constitutes four-fifths of the width of the body. There is an axial funnel tube and an aboral pole with a row of long, branched, aboral papillae ( Fig. 5 ). Reliable identification may only prove reliable thorough morphological examination of adult individuals and DNA analyses.

Geographical distribution: This species occurs in warm waters. Genetically its occurrence was confirmed off Villefranche sur Mer (Ligurian Sea) and the Adriatic Sea (Mediterranean), the north-eastern Pacific off the Californian coast and in the north-west Atlantic at Woods Hole, Massachusetts ( Podar et al., 2001; Bayha et al., 2004; Johansson et al., 2018; this study). The species is also known from morphological studies in the Mediterranean Sea ( Chun, 1880; Mertens, 1833; Galil & Gevili, 2013; Shiganova & Malej, 2009).

In an extensive study of warm-water ctenophores, Harbison et al. (1978) showed that Beroe cucumis is widespread also in the tropical and subtropical Atlantic. However, he highlighted ( Harbison, 2001) that the species he called Beroe cucumis sensu Mayer after Harbison et al. (1978), is not the same as the one from Greenland described by Fabricius (1780). The same opinion was expressed by Wrobel & Mills (1998) after study of individuals from the Pacific coast of the USA.

We suppose that all these individuals listed as B. cucumis , but found outside the cold-water areas, belong to Beroe pseudocucumis: Spanish coast, Madeira, the Canary Islands, the Caribbean and from the east coast of the USA to southern Brazil ( Bayha et al., 2004; Oliveira & Migotto, 2006; Moss, 2009; Oliveira et al., 2016). A few studies mentioned similar individuals from the Indian Ocean and the Arabian Sea ( Harbison et al., 1978; Gul & Jahangir, 2019). It is highly likely that these also are the warm-water Beroe pseudocucumis , also inhabiting the Indo-Pacific ( von Drygalski, 1909; Bigelow, 1919).

Habitat: Warm water, inshore and offshore (F. Lombard, pers. comm; Shiganova & Malej, 2009.); widespread in tropical and subtropical waters.

Figures

Figure 5. Beroe pseudocucumis. A, general view of adult ctenophore with meridional and paragastal canals; B, lateral view; C, view of meridional and paragastal canals and dense diverticulae, which does not anastomose with each other; D, axial funnel tube and aboral pole with a row of long branched aboral papillae (photographs by T. Makovec and T.Shiganova, from Shiganova & Malej, 2009).