Systematic affinities of Zygophylacidae (Cnidaria: Hydrozoa: Macrocolonia) with descriptions of 15 deep-sea species Author Gu, Zhangjie Author Ruthensteiner, Bernhard Author Moura, Carlos J. Author Liu, Lihua Author Zhang, Rui Author Song, Xikun text Zoological Journal of the Linnean Society 2022 Zool. J. Linn. Soc. 2022-06-17 196 52 87 http://zoobank.org/22984f44-21e0-43ab-9d46-547c8306448a journal article 133182 10.1093/zoolinnean/zlac036 f1c43083-ab5f-4130-82f0-0418e8954791 0024-4082 7035312 22984F44-21E0-43AB-9D46-547C8306448A ZYGOPHYLAX BIARMATA BILLARD, 1905 ( FIG. 7 ) Zygophylax biarmata : Ramil & Vervoort, 1992: 59–65 , figs 11e–h, 12a–i, 13e, f (synonymy). Type locality: Bay of Biscay , north-east Atlantic ; 411 m . Specimens examined: Three colonies from the Gulf of Cadiz, one fertile; see details in Supporting Information, Table S1 . Molecular sequences: 16S rRNA gene ( Moura et al. , 2008 , 2012 ); see sequence details in Supporting Information, Table S3 . Measurements: See Supporting Information, Table S2 . Description: Trophosome. Colonies upright, about 0.9 cm high ( Fig. 7A ). Hydrocaulus geniculate, polysiphonic, unsegmented, branching regularly ( Fig. 7A, B ). Hydrocladia coplanar, forming angles of 60°– 90° with the hydrocaulus ( Fig. 7B ), dichotomously branched, mono- or polysiphonic, with irregular nodes ( Fig. 7B, C ), axillary hydrothecae present at the branching sites ( Fig. 7D ). Hydrothecae alternating regularly in one plane, forming angles of 60°–90° with the longitudinal axes of the corresponding hydrocladia ( Fig. 7C ), short-pedicellate, tubular, the distal part straight or curved away from the internode and forming angles of about 30° with the proximal part; diaphragm oblique, margin slightly everted, with two to seven renovations ( Fig. 7C, E, G ). A tubular nematotheca present at apophyses of hydrocladia, with one to six renovations ( Fig. 7C, E, F ). Figure 5. Type materials (all paralectotypes) of five Zygophylax species deposited in the Zoologische Staatssammlung München. A–F, Z. abyssicola ( Stechow, 1926 ) , ZSM 20043537–ZSM 20043542; G, H, Z. africana Stechow, 1923 , ZSM 20041574, ZSM 20043579; I–M, Z. curvitheca Stechow, 1913 , ZSM 20043570–ZSM 20043574; N–Q, Z. pacifica Stechow, 1920 , ZSM 20041554–ZSM 20041556, ZSM 20043569; R–U, Z. valdiviae Stechow, 1923 , ZSM 20041566–ZSM 20041569. Scale bars: A–U = 2 cm. Figure 6. Type material of Zygophylax africana Stechow, 1923 . A, various colonies; B, portion of polysiphonic hydrocaulus with four monosiphonic hydrocladia, the left and the right arrows indicate an axillary hydrotheca and a nematotheca, respectively; C, hydrothecal diaphragm (lower arrow) and renovations (upper arrow); D, magnification of the nematotheca in B, the arrow indicates a diaphragm within the nematotheca. From samples: A, ZSM 20040731, the arrow indicates the lectotype, other colonies are parelectotypes; B–D, ZSM 20041574, paralectotype. A–D, near Cape Town, South Africa. A–D, light microscope images. Scale bars: A = 1 cm; B = 1 mm; C, D = 100 µm. Figure 7. Zygophylax biarmata Billard, 1905 . A, two colonies; B, hydrocaulus with coppinia; C, hydrothecal arrangement along a hydrocladium; D, an axillary hydrotheca (arrow); E, a hydrotheca with diaphragm (left arrow) and basal nematotheca (right arrow); F, magnification of a nematotheca; G, distal part of a hydrotheca showing multiple renovations. From samples: A–G: ZSM 20220294, Gulf of Cadiz. A, B, D, E, light microscope images; C, F, G, SEM images. Scale bars: A, B = 2 mm; C = 200 µm; D = 500 µm; E = 100 µm; F, G = 50 µm. Gonosome: Gonothecae clustering into coppiniae on hydrocaulus ( Fig. 7A, B ); coppiniae with dichotomously branched defensive tubes and hydrothecae. The morphology of individual gonothecae could not be established properly without destructive methods, and the coppiniae in the present material are obscured by adhering particles, not allowing a detailed examination to be done. Distribution: Gulf of Cadiz ( Moura et al. , 2012 ; this study); Bay of Biscay north-west of Spain ; the Azores; Madeira; the Canary Islands ; the east coast of South Africa ; the Madagascar area; the Zanzibar area (See Ramil & Vervoort, 1992 ).