Physalia cf. utriculus (Gmelin, 1788)

Estrada-González, Mariae C., Agüero, José & Mendoza-Becerril, María A., 2023, Medusozoans from the Mexican Pacific: a review based on historical literature and recent observations, Journal of Natural History 57 (1), pp. 784-853 : 835-836

Physalia cf. utriculus (Gmelin, 1788)

( Figure 9A, B )

Material examined

1 colony; Balandra Beach, La Paz Bay , Baja California Sur, 24°19′13′′N, 110°19′27′′W; water surface; 2016; photograph . – 1 colony; Tarabillas Beach, La Paz Bay , Baja California Sur, 24.477°N, 110.687°W; water surface; 9 November 2017; field observation . – 1 colony; Balandra Beach, La Paz Bay , Baja California Sur, 24.320°N, 110.324°W; water surface; 24 April 2015; photograph . – 1 colony; El Tecolote Beach, La Paz Bay , Baja California Sur, 24.341°N, 110.306°W; stranded on the beach; 27 February 2021; ECO-CH-Z 11803 .

Identification (after Yanagihara et al. 2002)

Colony with a triangular, gas-filled pneumatophore that allows it to float. Pneumatophore formed by a transparent to blue membrane and pneumatosaccus invaginated in the apical region. Polymorphic organisms of blue colouration, attached to the pneumatophore and organised in gastrozooids that lack tentacles, gonodendron bears reproductive structures and several elongated and coiled tentacle palpons. A single fishing tentacle is present.

Distribution

New record for the west coast of the Gulf of California. The genus has been recorded on the north-east coast of the MP ( Gómez-Aguirre 1991).

Remarks

It is impossible to corroborate whether the records of P. physalis from the north-east coast of the MP by Gómez-Aguirre (1991) correspond to P. utriculus because there is no morphological or cnidome description of the specimens. In addition, it was impossible to access the specimens since they were not found in the place where they were deposited by Gómez-Aguirre (M.E. Hendrickx, personal communication, 1 August 2018). There is morphological evidence in the literature that distinguishes the two species, although the most mentioned is the presence of a single fishing tentacle in P. utriculus and multiple tentacles in P. physalis ; moreover, the cnidome and colony size between species are different ( Table 3 ) ( Hulet et al. 1974; Fenner et al. 1993; Yanagihara et al. 2002; Bardi and Marques 2007; Gershwin et al. 2010). Even the discharge of the nematocysts is different between species according to the solution employed ( Wilcox et al. 2017), and the symptoms caused by the sting differ ( Cegolon et al. 2013). In agreement with morphological, cnidome and distributional evidence, it is suggested that the species reported from the MP in this study is P. cf. utriculus . Indeed, from 2016 to date, at different times of the year in La Paz Bay, the same morphotype has been observed. Molecular data must be incorporated to define the related species, including specimens from the Atlantic Ocean.

Figures

Figure 9. Physalia cf. utriculus (Gmelin, 1788): A, colony; B, pneumatophore; C, undischarged heterotrichous anisorhiza nematocysts; D, heterotrichous anisorhiza discharged nematocyst. Scale bars: 20 μm. Photograph taken by Claudia Jeannette Pérez Estrada (A).