Zygophylax medeae, Peña Cantero, 2020

Peña Cantero, Álvaro L., 2020, On six new species of Zygophylax Quelch, 1885 (Cnidaria, Hydrozoa Zygophylacidae) from the New Calendonian region, Zootaxa 4822 (3), pp. 389-404 : 397-400

publication ID	https://doi.org/ 10.11646/zootaxa.4822.3.4
publication LSID	lsid:zoobank.org:pub:B87B0063-9D1B-4FD7-A2B4-EB3622FCE68A
DOI	https://doi.org/10.5281/zenodo.4401699
persistent identifier	https://treatment.plazi.org/id/903897FE-7295-4144-8510-EADE9EB347FA
taxon LSID	lsid:zoobank.org:act:903897FE-7295-4144-8510-EADE9EB347FA
treatment provided by	Plazi
scientific name	Zygophylax medeae
status	sp. nov.

Treatment

Zygophylax medeae sp. nov.

( Figs 1E View FIGURE 1 , 6 View FIGURE 6 , 7A View FIGURE 7 )

urn:lsid:zoobank.org:act:903897FE-7295-4144-8510-EADE9EB347FA

Material examined. BIOGEOCAL Stn CP 205, 22°40.61’– 22°41.07’S, 166°28.01’– 166°27.63’E (off SW of New Caledonia), 1350–1380 m, 08.04.1987: 27-mm-high stem, with gonothecae (all in slide) (Holotype, MNHN-IK-2019- 2045) GoogleMaps .

Description. Stem polysiphonic, 27 mm high, with only a few hydrocladia and three hydrothecae left ( Fig. 1E View FIGURE 1 ). Hydrocladial apophyses large ( Figs 6A, D View FIGURE 6 , 7A View FIGURE 7 ), much larger than hydrothecal apophyses, markedly separated from hydrocladia. Hydrocladia with a basal oblique ring ( Fig. 6A, D View FIGURE 6 ). Basal part of first internode slightly swollen ( Fig. 6A, D View FIGURE 6 ).

Hydrocladia monosiphonic ( Fig. 1E View FIGURE 1 ), divided into very long internodes; hydrothecae relatively separated ( Fig. 1E View FIGURE 1 ). Angle between apophyses and hydrocladia 80°.

Hydrothecal apophysis short, apparently without nematothecae. Distinct separation between hydrothecal apophysis and hydrothecal pedicel. Hydrothecae tubiform ( Figs 6 View FIGURE 6 B–D, 7A), more or less symmetrical, roughly straight, though slightly convex at adcauline side and slightly concave at abcauline side. Pedicel long ( Figs 6 View FIGURE 6 C–D, 7A), separated from hydrotheca by a slightly oblique diaphragm, marked by a thin ring of perisarc ( Figs 6 View FIGURE 6 C–D, 7A). Aperture circular, rim even with up to six renovations ( Fig. 6C View FIGURE 6 ). Diameter of hydrothecae smoothly increasing to aperture.

Only a few nematothecae on accessory tubes present. Nematothecae elongate, cylindrical ( Fig. 6 View FIGURE 6 E–F).

Three gonothecae present ( Fig. 1E View FIGURE 1 ). Gonotheca outline fusiform, but distal part with two opposing arms, each with a distal wide aperture ( Figs 1E View FIGURE 1 , 6F View FIGURE 6 ).

Measurements (in µm). Hydrothecae: length of abcauline wall 650–680, length adcauline wall 630–650, diameter at aperture 160–190, diameter at diaphragm 100, basal diameter 80–90, length of pedicel 480–500. Nematothecae: height 300–320, diameter at aperture 25, maximum diameter 40–50. Gonothecae: height 850–870, diameter at aperture c. 120, maximum diameter 350–380.

Remarks. The scarcity of material prevents me from determining the arrangement of the hydrothecae and the number of nematothecae on apophyses.

Zygophylax medeae sp. nov. is similar to Z. recta Jarvis, 1922 by the shape of the hydrotheca, although they are clearly distinguishable by the length of the pedicel, markedly much shorter in Z. recta . They also differ in the size of the hydrothecae, smaller in Z. recta (e.g. 150 µm in diameter at aperture), and nematothecae, shorter in Jarvis’s species (70–100 µm in height).

Etymology. The specific name medeae is a dedication to my daughter Medea Peña Sancho.