Pasya quadridentata (Ellis and Solander, 1786)

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 : 830-831

Pasya quadridentata (Ellis and Solander, 1786)

( Figure 7K, L )

Material examined

Several colonies, polyp, with gonophores; Punta Los Muertos , Baja California Sur, 24.248°, 110.150°W; depth 1–2 m; 20 July 2018; on the alga Codium simulans ; ECO-CH-Z 11762 .

Identification (after Calder 1991; Miranda et al. 2011)

Colonies erect; hydrocaulus monosiphonic, unbranched, divided into internodes by distinct oblique nodes. Basal athecate internodes separated from the thecate internodes by an oblique node; thecate internodes with 1–3 pairs of opposite hydrothecae. Hydrothecae contiguous and continuous in front of internodes, separated across back. Proximal pair of a group curved outwards with hydrothecal axes oblique to internodal axis, distal pair more straight; adnate parts of adcauline wall straight, free part convex; abcauline wall concave except for basal part. Hydrothecal margin with two large rounded lateral cusps and a smaller median adcauline cusp. Operculum formed by two valves, a large abcauline and a smaller adcauline. Gonotheca with six rounded, transverse ridges, arising by short pedicels from hydrocaulus just beneath the hydrotheca on the first thecate internode.

Distribution

Previously recorded on the west coast of the Gulf of California, Baja California ( Fraser 1938c), making it a new record for the south-western gulf in Baja California Sur. In the MP, it has been recorded from Baja California and Baja California Sur ( Fraser 1938a, 1948).

Remarks

The specimen fits the descriptions of the species Dynamena quadridentata . However, this paper maintains the assignment to the genus Pasya , based on robust molecular evidence ( Moura et al. 2011) and the historical nomenclature of the taxon ( Calder 2013). The genus Pasya requires revision to clarify its taxonomic status.

Figures

Figure 7. (A, B) Ventromma halecioides (Alder, 1859): A, hydrocaulus; B, hydrotheca. (C, D) Monotheca flexuosa (Bale, 1894): C, hydrocaulus; D, hydrotheca. (E, F) Plumularia floridana Nutting, 1900: E, hydrocaulus; F, hydrotheca. (G, H) Dynamena crisioides Lamouroux, 1824: G, colony; H, hydrotheca. (I, J) Dynamena disticha (Bosc, 1802): I, colony; J, hydrotheca. (K, L) Pasya quadridentata (Ellis and Solander, 1786): K, colony; L, gonotheca. Scale bars: A, H, I, K, L = 500 μm; B, D = 100 μm; C, E = 250 μm; F, J = 200 μm; G = 1 cm. Drawings made by Nicholas Bezio.