Zygophylax polycarpa Vervoort & Watson, 2003

Galea, Horia R., Maggioni, Davide & Galli, Paolo, 2022, On some species of Zygophylax Quelch, 1885 (Cnidaria: Hydrozoa: Zygophylacidae) from off New Caledonia, Zootaxa 5214 (1), pp. 1-46 : 22

Zygophylax polycarpa Vervoort & Watson, 2003

( Figs 12–14 , 25 ; Tables 6 , 8 )

Zygophylax polycarpa Vervoort & Watson, 2003: 75 , figs 11E, 12.— Campos, 2017: 141, fig. 31.

Material examined. MNHN-IK-2015-2994, KANADEEP 2 Stn. PL743-04 : three colonies, 0.5–2.5 cm high, largest bearing a basal coppinia.—MNHN-IK-2019-2094, KANACONO Stn. DW 4755: a colony composed of three stems, tallest 9.5 cm high and bearing a coppinia.—MNHN-IK-2019-2095, KANACONO Stn. DW 4747: six colonies, 5.5–22 cm high, some bearing coppiniae; GenBank: OP724379 .—MNHN-IK-2019-2096, KANACONO Stn. DW 4737: many sterile colonies, 3.5–9.5 cm high. —MNHN-IK-2019-2097, KANACONO Stn. DW 4746: a ca. 9 cm high, sterile colony.—MNHN-IK-2019-2098, KANACONO Stn. DW 4785: many colonies and fragments, 2.5–10 cm high, all but one sterile; GenBank: OP724380 .—MNHN-IK-2019-2099, KANACONO Stn. DW 4749: many colonies, 3.5–11 cm high, some bearing coppiniae .

Description. Colonies erect, to 22 cm high, quite stiff, flabellate, straw-colored, arising from bunch of branched, anastomosed stolonal fibers creeping around the substrate, generally a coral; branching irregular, rather scant, occasionally on only one side of the stem, in a single plane; up to 2 nd order branches; lower-order branches given off at a wide angle with the stem, then rapidly curving upwards; usually very long, tending to reach the height of the main stem itself; stem and branches fascicled, grading to monosiphonic distally; stems up to 3 mm wide basally; accessory tubes running parallel to the main tube, either linear in aspect or tortuous in places, occasionally branched, anastomosed, communicating between them through large, ovoid pores in the perisarc; main tube slightly geniculate, usually undivided, although rare, transverse constrictions of the perisarc could be present; composed of a succession of modules, each comprising a well-developed apophysis (together with its axillar hydrotheca atop its own apophysis) supporting a cladium, two alternate, comparatively shorter apophyses above (each supporting a hydrotheca), and a second cladial apophysis (and its axillar hydrotheca borne on its apophysis) on side opposite to that of its proximal counterpart; apophyses not very distant from one another, aperture of a given hydrotheca either reaching or surpassing the level of the apophysis of next hydrotheca; apophyses ending distally in a variouslymarked, transverse constriction of the perisarc. Cladia pinnately-arranged along the stem and branches, to 21 mm long, given off at a wide angle, the two rows coplanar; strictly monosiphonic, unless they further elongate, become increasingly fascicled, and eventually transform themselves into lateral branches; undivided,equivalents of internodes up to 36 per cladium, rather short, almost collinear, each bearing a quite short, latero-distal apophysis supporting a hydrotheca; apophyses alternate, the two rows of hydrothecae coplanar. Hydrothecae short-pedicellate, pedicels expanding widely and merging smoothly into the thecal wall, demarcation internal, through a thick diaphragm with central, circular pore with slightly upwardly-raised internal edge; adaxial wall of hydrotheca distinctly convex in proximal half, straight distally; abaxial wall imperceptibly concave proximally, then straight; distal part of the theca tubular; aperture transversely-set, large, circular, rim even, barely everted, usually a few closely-set renovations; hydrothecal wall finely and densely striated transversely throughout. Nematothecae scant; when present, usually occurring on the apophyses of some axillar and cauline hydrothecae; a nematotheca was also present on a stem “internode”, a short distance above the apophysis of a hydrotheca; urn-shaped, lateral wall either almost parallel or slightly converging proximally, aperture transversely-set, circular, rim even, slightly everted. Coppinia muffshaped, to 4.5 cm long and 1 mm wide, composed of closely-packed, though individual gonothecae, arising from the accessory tubes of the stem/branch, and pointing in all directions; large, club-shaped, gradually tapering proximally into a long, indistinct, smooth to wrinkled pedicel; widest in middle, then tapering slightly distally and, there, with distinctly wrinkled perisarc; aperture set transversely, rounded, closed by perisarc sheet; perisarc finely and densely striated transversely throughout.

Remarks. The independent gonothecae, similar in shape and size to those of Z. niger Galea, 2019 , are peculiar for the genus.

Distribution. Three Kings Islands, New Zealand ( Vervoort & Watson 2003), New Caledonia (present study).

Figures

FIGURE 12. Zygophylax polycarpa Vervoort & Watson, 2003 (part). Apical part of a colony. Scale bar: 1 mm.

FIGURE 13. Zygophylax polycarpa Vervoort & Watson, 2003 (continued).A–D. Cauline (A, B) and axillar (C, D) hydrothecae, with (A, C) and without (B, D) nematothecae on their apophyses. All from sample MNHN-IK-2019-2095. Scale bar: A–D = 300 µm.

FIGURE 14. Zygophylax polycarpa Vervoort & Watson, 2003 (concluded). A. Cladial hydrotheca. B. Nematotheca on the apophysis of an axillar hydrotheca. C. Hydrothecal diaphragm; adaxial (ad) and abaxial (ab) sides are shown. D. Gonotheca.All from sample MNHN-IK-2019-2095. Scale bars: B, C = 100 µm; A = 300 µm; D = 1 mm.

FIGURE 25. Phylogenetic hypothesis for the Zygophylaciidae based on the 16S rRNA gene. Numbers at nodes refer to support values of the maximum likelihood, Bayesian inference and maximum parsimony analyses, respectively, and are shown only when> 70 and 0.7. Sequences generated in this study are followed by voucher numbers.