Aglaophenia pinguis Fraser, 1938

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 : 821-823

Aglaophenia pinguis Fraser, 1938

( Figure 6A–C )

Material examined

4 colonies, polyp, without corbulae; Agua de Yepiz, La Paz Bay, Baja California Sur, 24.288° N, 110.630°W; depth 0–1 m; 24 June 2018; on undetermined algae and coralline algae; ECO-CH-Z 11790. – 3 colonies, polyp, with corbulae, female; Punta Los Muertos, Baja California Sur, 24.248°N, 110.150°W; depth 0–1 m; 20 July 2018; on the algae Amphiroa valaeinoides and Chondria arcuata , and on coral; ECO-CH-Z 11768. – 1 colony, polyp, with corbulae, female; El Mogote Sand Bar, La Paz Bay, Baja California Sur, 24.159°N, 110.341°W; depth 0–2 m; 1 July 2019; on ascidian and unattached; ECO-CH-Z 11797. – 2 colonies, polyp, with corbulae; El Tecolote Beach, La Paz Bay, Baja California Sur, 24.341°N, 110.306° W; depth 0–5 m; 27 February 2021; on undetermined algae; ECO-CH-Z 11802.

Identification (after Fraser 1938b, 1948)

Colonies erect, hydrocaulus monosiphonic, alternately branched, divided into internodes by indistinct oblique nodes. Internodes with a distal hydrocladial apophysis, a frontal mamelon or pseudonematotheca, and three cauline nematothecae, one inferior and two axillaries on frontal and posterior position, respectively. Hydrocladia unbranched, divided into thecate internodes by slightly oblique distinct nodes. Each internode bearing one hydrotheca, one median inferior nematotheca, and a pair of lateral nematothecae; two distinct internodal septa for internode, at the bases of intrathecal septum and lateral nematothecae, respectively. Hydrothecae with abcauline wall convex distally, hydrothecal margin with nine cusps, one median and four lateral pairs, median and first pair equal size and large, the remaining cusps diminishing in size from front to back. Median inferior nematotheca adnate to abcauline wall of hydrotheca basally, reaching three-quarters height of the hydrotheca; lateral nematothecae reach beyond hydrothecal margin. Female corbulae closed, pod-shaped, each occurring in place of a hydrocladium on branches, with one cormidia basally. Either side of rachis with 9–10 fused nematocladia.

Distribution

Previously recorded on the west coast of the Gulf of California in Baja California and Baja California Sur ( Fraser 1938b, 1948) and for the rest of the gulf in Nayarit ( Fraser 1948). In the MP, it has been recorded off the coasts of Baja California and Baja California Sur ( Fraser 1948).

Remarks

The specimens conform to the description of A. pinguis Fraser, 1938b , agreeing on the characteristics of a long colony of short hydrocladia, with two distinctive septa per hydrocladial internode, and the lower nematotheca does not reach the height of the hydrothecal margin. When corbulae are present, they are abundant per colony ( Calder et al. 2009; Mendoza-Becerril et al. 2020). As a way to enrich the original description of A. pinguis Fraser (1938b, 1948 ), specimens from four localities were reviewed, collected at distance of 60–78 km from the type locality (San Francisco Island, 24°49′50′′N, 110°34′W) defined by Calder et al. (2009). Fraser (1938b) described the presence of two nematothecae on the hydrocaulus (one in the inferior position and the other one superior) and two hydrocladial processes on the apophysis (one frontal and one posterior). These characteristics are redefined with the terminology of the distinctive characteristics for the genus Aglaophenia ( Ansín Agís et al. 2001; Soto Àngel and Peña Cantero 2017), such as the presence of three nematothecae in each internode of the hydrocaulus, one lower and two flanking the apophysis in frontal and posterior positions, respectively, in addition to the presence of a pseudonematotheca or mamelon on the apophysis. Similarly, the hydrothecal margin shows the small, straight frontal cusp and four lateral pairs of cusps, whose size decreases from the adcauline to the abcauline position. Thus, A. pinguis is distinguished from A. diegensis (Torrey, 1902) , A. longicarpa ( Fraser, 1938b) and A. propinqua ( Fraser, 1938b) , which are recorded in the same area (see Mendoza-Becerril et al. 2020). Also, thanks to this new revision, the specimen Aglaophenia sp. recorded by Mendoza-Becerril et al. (2020) is reassigned as A. pinguis .

Figures

Figure 6. (A–C) Aglaophenia pinguis Fraser,1938; A, hydrocaulus; B, hydrotheca; C, hydrotheca inferior nematotheca. (D–F) Aglaophenia symmetrica Fraser, 1938: D, hydrocaulus; E, hydrotheca; F, hydrotheca inferior nematotheca. (G–I) Macrorhynchia philippina Kirchenpauer, 1872: G, hydrocaulus; H, hydranth; I, hydrotheca inferior nematotheca. (J, K) Halopteris violae Calder, Mallinson, Collins and Hickman, 2003; J, hydrocaulus; K, hydrotheca. Scale bars: A, J = 500 μm; B, E, G, H, K = 200 μm; C, F, I = 100 μm; D = 1 cm. Drawings made by Nicholas Bezio.