Zygophylax cervicornis
Creators: name: Galea, Horia R.
name: Maggioni, Davide
name: Galli, Paolo
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Hydrozoa
Leptothecata
Zygophylacidae
Zygophylax
Zygophylax cervicornis

description: Zygophylax cervicornis (Nutting, 1905)
(Figs 4, 5, 25; Tables 3, 8)
Lictorella cervicornis Nutting, 1905: 946, pl. 4 fig. 1, pl. 10 figs 5–9.
Zygophylax cervicornis – Schuchert, 2015: 332, fig. 7 (cum syn.).
Material examined. MNHN-IK-2015-3065, KANADEEP 2 Stn. CP 5108: a flabellate colony, 9 × 9 cm, bearing four coppiniae (largest 6 × 4 mm); GenBank: OP724366.— MNHN-IK-2019-2147, KANACONO Stn. DW 4698: a colony of originally undeterminable size, now broken into four pieces, one of them (5 cm high) bearing a fullyformed coppinia (10 × 4 mm), and another one (4.5 cm high) with an incipient coppinia (6 × 1.5 mm); GenBank: OP724367.
Description. Colonies erect, flabellate, largest 9 × 9 cm, relatively stiff, arising from dense stolonal network firmly adhering to various substrates; stem and branches (up to the 3 rd order) coplanar, fascicled for most of their length; stem 1.5 mm wide basally; auxiliary tubes straight, running parallel to the main tube, communicating through lateral, rounded pores in the perisarc, bearing scattered, long, club-shaped nematothecae; main tube straight, not regularly divided into internodes, but bearing occasional transverse constrictions of the perisarc, composed of successive modules, each comprising proximally a long apophysis (together with its axillary hydrotheca atop its own apophysis) supporting a cladium, two alternating, slightly shorter apophyses above, each supporting a hydrotheca, and a distal apophysis (with its axillar hydrotheca) supporting another cladium, given off on side opposite to its proximal counterpart; all apophyses coplanar. Cladia straight, up to 14 mm long, either monosiphonic or lightly fascicled proximally, occasionally becoming elongate, polysiphonic, and eventually transform into lower-order cladia-bearing branches; division into internodes irregular, through distinct, transverse nodes, each comprising 1–5 hydrothecal apophyses; up to 41 apophyses per cladium, alternate, coplanar, comparatively shorter than their cauline counterparts. Hydrothecae pedicellate; pedicels well-developed, either smooth-walled or with generally 1, occasionally 2, rarely 3 and exceptionally 4 distinct annuli proximally; pedicels gently flaring from base to distal end, and there merging smoothly with the hydrothecal wall, demarcation internal, though a transversely- to obliquelyset, relatively thin diaphragm, bearing centrally a rounded foramen (with slightly upturned edge) for the passage of the hydranth; adaxial wall of theca slightly sigmoid, convex in proximal half, concave in distal half; abaxial wall straight for ca. 2/3 of its proximal length, and slightly concave distally; distal part of hydrotheca cylindrical, proximal part tapering gently; perisarc thin, smooth; aperture transversely-set, circular, slightly everted, rim even, with up to 9 renovations. Nematothecae occurring indifferently singly or in pairs, on the apophyses supporting both the cladia and hydrothecae, occasionally (apparently only) singly on the apophyses of axillar hydrothecae; short, barrelshaped, tapering both above and below, aperture small, circular. Coppinia arising from both the stem and branches, composed of closely-set, though individual gonothecae, among which are given off protective tubuli that branch extensively and dichotomously above the gonothecae, branchlets often anastomosing and bearing numerous long, digitiform nematothecae; gonothecae inverted-conical, borne on indistinct pedicels, distally provided with a couple of upwardly-directed funnels, each bearing terminally a large, circular aperture.
Remarks. The New Zealand record by Vervoort & Watson (2003: 72) likely belongs to another species, due to the presence of a couple of nematothecae on the hydrothecal pedicels; in addition, their material was sterile and, hence, difficult to identify.
Distribution. Hawaii (Nutting 1905, as L. cervicornis), Japan (Schuchert 2015), New Caledonia (present study).
description: Published as part of Galea, Horia R., Maggioni, Davide & Galli, Paolo, 2022, On some species of Zygophylax Quelch, 1885 (Cnidaria: Hydrozoa: Zygophylacidae) from off New Caledonia, pp. 1-46 in Zootaxa 5214 (1) on pages 9-12, DOI: 10.11646/zootaxa.5214.1.1, http://zenodo.org/record/7381826