Sanderia, Goette, 1886

Morandini, André C. & Gul, Shahnawaz, 2016, Rediscovery of Sanderia malayensis and remarks on Rhopilema nomadica record in Pakistan (Cnidaria: Scyphozoa), Papéis Avulsos de Zoologia 56 (15), pp. 171-175 : 172

Remarks on Sanderia species

Sanderia malayensis Goette, 1886 was originally described from Singapore, Malayan Archipelago ( Goette, 1886); later it was reported from several places like Japan (as Neopelagia eximia Kishinouye, 1910 ), Philippines and Suez Canal ( Kramp, 1961). Stiasny (1937) reported the species from northern Arabian Sea (off-Karachi along Pakistani coast and Gulf of Oman), and Gulf of Aden. Two small specimens (1 and 1.5 cm bell diameter) wrongly stated as in Pelagia -stage were collected off-Karachi on 8 November 1933 during the John Murray Expedition (1933-34). According to Kramp (1961:331) the species has heart-shaped gastric pouches each bordered externally by about 24-30 finger-like gonadal papillae; but our specimens although agreeing with the description of the species, have more papillae (35-40) than stated, and the shape of the gastric pouches vary slightly. Vanhöffen (1902:38) while observing specimens from the Gulf of Aden mentioned the number of gonadal papillae to be 24, tentacles compressed laterally and nematocysts concentrated on the outer portion of tentacles. Browne (1926:110-112) observed specimens collected at the Suez Canal area ranging from 1.2-3.5 cm bell diameter and having variation in rhopalia number. Stiasny (1937:226) however, was not correct while identifying Pelagia -stage specimens of Sanderia from off-Karachi, Pakistan. Such specimens must correspond to a Pelagia species, based on the information about the life cycle of Sanderia malayensis ( Uchida & Sugiura, 1975, 1978) and our own observations that Sanderia ephyrae are released with already 16 rhopalia and 32 lappets. For other specimens observed by Stiasny (1937:225-227), the author did not mention the number of gonadal papillae, but if we focus on his pl. 1, fig. 1, the two specimens are showing to have approximately 40 papillae on each gastric pouch, similar to our observations.

Sanderia malayensis has only one congener, S. pampinosus , which bears horseshoe-shaped gastric pouches with 34-44 gonadal papillae ( Gershwin & Zeidler, 2008). For the authors, these are the main features that distinguish both species. However, by inspection of the holotype specimen (ZMB 2622, Fig. 2A ) it is possible to observe that the contour of the gastric pouch is variable and the gonadal papillae are thicker than in other specimens. Additionally, another specimen observed by Goette (ZMB 2621, Fig. 2B ) and in young specimens of S. malayensis we cultivated in the laboratory of the first author ( Fig. 2 C-D), it is possible to state that the gastric pouch contour is horseshoe-shaped while, horseshoe to heart-shaped with 35-40 gonadal papillae in the Pakistani specimens ( Fig. 1 C-D). These observations raise the question whether, the shape of the gastric pouch can pass through developmental changes during growth and that we might be dealing with a single species of the genus with a wider distributional area. Our suggestions, to solve this issue, are to cultivate this jellyfish species to maturity and perform comparative molecular studies with specimens from different areas.

Figures

FIGURE 1: Freshly collected specimen of Sanderia malayensis Goette, 1886 from Pakistani coast, off-Karachi. Bell diameter 11 cm: (A) Exumbrellar view showing transparent umbrella with numerous nematocyst warts, (B) Subumbrellar view showing gastric pouches in closeup, note the heart-shape contour of gastric pouches.

FIGURE 2: Sanderia malayensis Goette, 1886 specimens in subumbrellar view: (A) Type specimen ZMB 2622, (B) Type specimen ZMB 2621, (C, D) Specimens cultivated from ephyra. Note the shape of gastric pouches in all individuals.