Zygophylax tankahkeei, Gu & Ruthensteiner & Moura & Liu & Zhang & Song, 2022

Gu, Zhangjie, Ruthensteiner, Bernhard, Moura, Carlos J., Liu, Lihua, Zhang, Rui & Song, Xikun, 2022, Systematic affinities of Zygophylacidae (Cnidaria: Hydrozoa: Macrocolonia) with descriptions of 15 deep-sea species, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 196, pp. 52-87 : 77-78

ZYGOPHYLAX TANKAHKEEI GU & SONG SP. NOV.

( FIGS 13E, F , 14B , 19 )

Z o o b a n k r e g i s t r a t i o n: urn: lsid: zoobank. org:act: A5BD0B58-428E-473F-A080-206CCAC77CDE.

Type locality: South China Sea ; 2359 m.

Etymology: The specific name honours the founder of Xiamen University, Tan Kah Kee, as well as the research vessel Tan Kah Kee (served Xiamen University since 2016) that collected the type material of this species, and in memory of the University’s 100th and 101st Anniversary Celebration (1921–2022).

Type material: Holotype, XUMB6200-1 , with one coppinia; paratype, XUMB6200-2 , infertile; see Supporting Information, Table S1 .

Figures

Figure 13. Hydrothecal arrangement and gonothecae of three new species. A, B, Zygophylax lighti sp. nov.; C, D, Z. pseudosibogae sp. nov.; E, F, Z. tankahkeei sp. nov. A, C, E, hydrothecal arrangement, the bases of hydrothecal pedicels are unilateral arranged, and the distal hydrothecal ends alternately turn left and right, respectively; B, D, F, gonothecae (with defensive tubes). Scale bars: A–F = 500 µm.

Figure 14. Morphological comparisons of selected zygophylacids with curved hydrothecae. A, Zygophylax lighti sp. nov.; B, Z. tankahkeei sp. nov.; C, Z. pseudosibogae sp. nov.; D, E, Z. sibogae Billard, 1918; F, Z. unilateralis Totton, 1930; G, Z. convallaria (Allman, 1877); H, Z. infundibulum Millard, 1958; I, Z. concinna (Ritchie, 1911); J, Z. reflexa (Fraser, 1948); K, Z. adhaerens (Fraser, 1938), hydrothecal basal portion is adherent on the hydrocladium; L, Z. tizardensis Kirkpatrick, 1890; M, Z. kakaiba Campos, Marques, Puce & Pérez, 2016; N, Z. curvitheca Stechow, 1913; O, Cryptolaria prima Busk, 1858, the hydrotheca is almost completely immersed in the hydrocladium. A, XMUB7904, holotype; B, XMUB6200-1, holotype; C, ZSM 20220300, holotype; N, ZSM 20043572, paralectotype. The following images were redrawn from the related original descriptions: D, Schuchert (2003); E, Billard (1918); F, Totton (1930); G, Allman (1877); H, Millard (1958); I, Ritchie (1911); J, Fraser (1948); K, Fraser (1938); L, Kirkpatrick (1890), Hirohito (1995); M, Campos et al. (2016); O, Busk (1858), Ralph (1958). All arrows indicate hydrothecal indentations. Scale bars: A–D, F–I, L–O = 500 µm; E, J, K, unknown.

Figure 19. Type material of Zygophylax tankahkeei sp. nov. A, two colonies, holotype (left), paratype (right); B, portion of the polysiphonic hydrocaulus and a monosiphonic hydrocladium, and an axillary hydrotheca (arrow); C, arrangement of the hydrothecae in two different planes; D, a hydrotheca; E, magnification of a node (upper arrow) and apophysis (lower arrow); F–J, hydrothecal diaphragms (lower arrow in F, arrows in G, H), perisarc projection (upper arrow in F, and arrow in I) and distal renovations (J); K, L, the same nematotheca at different magnifications (arrows); M, coppinia; N, gonothecae (arrow) with repeatedly, dichotomously branched defensive tubes; O, P, isolated gonothecae, the arrows in P indicate three apertures. From samples: A, the left colony, XMUB6200-1, holotype; the right colony, XMUB6200-2, paratype; B–P: XMUB6200-1, holotype.A–P, South China Sea. A–C, F–I, K–M, O, light microscope images; D, E, J, N, P, SEM images. Scale bars:A = 5 mm; B, F, K, N = 500 µm; C, M, O = 1 mm; D, I, P = 200 µm; E, G, H, J, L = 100 µm.