Gonaxia perplexa Vervoort, 1993

Galea, Horia R. & Maggioni, Davide, 2021, An integrative study of some species of Gonaxia Vervoort, 1993 from off New Caledonia, with the establishment of Gonaxiidae as a new family of thecate hydroids (Cnidaria: Hydrozoa), Zootaxa 5004 (3), pp. 401-429 : 416

Gonaxia perplexa Vervoort, 1993

Figs 1H , 5E , 11 , 15 , 16 ; Table 3

Gonaxia perplexa Vervoort, 1993: 165 , figs 27C–D, 28.

Material examined. KANADEEP, Stn. DW 4977, MNHN-IK-2019-2068: a 2.3 cm high colony bearing ♀ gono- thecae.—KANADEEP, Stn. DW 5021, MNHN-IK-2019-2057: five colonies, 1.8–4.6 cm high, of which two bear ♀ gonothecae, and the remaining three bear ♂ gonothecae; GenBank: MZ 099703 (16S), MZ 099688 (18S), MZ 099672 (28S).—KANADEEP, Stn. DW 5037, MNHN-IK-2019-2058: four colonies, 3.2–4.5 cm high, two of which bear ♂ gonothecae, and the other two bear ♀ gonothecae; GenBank: MZ 099704 (16S).—KANADEEP, Stn. 5042, MNHN- IK-2019-2067: a 3 cm high colony bearing ♀ gonothecae .

Remarks. The distinctive hydrothecal shape ( Fig. 11A, B ) and the partly adnate male gonothecae ( Fig. 11C ) make this species easily recognizable. For a comprehensive description, refer to Vervoort (1993).

One of the male colonies in sample MNHN-IK-2019-2057 has one of its lowest cladia branched in the same manner as the stem, i.e. giving rise to 6 alternate, second-order cladia.

The so far unknown female gonothecae ( Figs 5E , 11D ) occur in several colonies examined here; similar to their male counterparts, about 660 µm wide, they only differ through their much wider apertures (ca. 330 µm).

Bathymetric distribution. Between 280–360 m ( Vervoort 1993; present study).

Figures

FIGURE 1. Species of Gonaxia dealt with in this study: G. bulbifera Vervoort, 1993 (A), G. crassicaulis Vervoort, 1993 (B), G. crusgalli Vervoort, 1993 (C), G. elegans Vervoort, 1993 (D), G. errans Vervoort, 1993 (E, unbranched form), G. incisa Galea, sp. nov. (F), G. cf. intermedia Vervoort, 1993 (G), G. perplexa Vervoort, 1993 (H), G. sinuosa Vervoort, 1993 (I), G. solenoscyphoides Galea, sp. nov. (J). Scale bar: 1 cm.

FIGURE 5. Gonothecae of several species of Gonaxia dealt with herein: G. crassicaulis Vervoort, 1993 (A: female, B: male), G. elegans Vervoort, 1993 (C), G. incisa Galea, sp. nov. (D), G. perplexa Vervoort, 1993 (E), G. sinuosa Vervoort, 1993 (F). Scale bar: 5 mm.

FIGURE 11. Gonaxia perplexa Vervoort, 1993. A. Portion of colony. B. Hydrotheca seen laterally. C, D. Male (C) and female (D) gonothecae. From sample MNHN-IK-2019-2057. Scale bars: B = 300 µm; A, C, D = 1 mm.

FIGURE 15. Phylogenetic hypothesis for Gonaxia species based on a 16S dataset. Numbers at nodes show maximum likelihood bootstrap values, Bayesian posterior probabilities, and maximum parsimony bootstrap values, respectively.

FIGURE 16. Phylogenetic hypothesis for the position of the Gonaxiidae Maggioni, fam. nov. within Macrocolonia, based on a multi-locus dataset. Numbers at nodes show maximum likelihood bootstrap values, Bayesian posterior probabilities, and maximum parsimony bootstrap values, respectively, and are shown only when at least two analyses demonstrated high support (> 0.9 for Bayesian posterior probabilities and> 75 for bootstrap values).