Caledoniana microgona Galea, 2015

Galea, Horia R. & Schuchert, Peter, 2019, Some thecate hydroids (Cnidaria: Hydrozoa) from off New Caledonia collected during KANACONO and KANADEEP expeditions of the French Tropical Deep-Sea Benthos Program, European Journal of Taxonomy 562, pp. 1-70 : 4-5

Caledoniana microgona Galea, 2015

Fig. 1C

Caledoniana microgona Galea, 2015a: 6 , figs 1C, 2E–G.

Material examined

PACIFIC OCEAN • a 2.4 cm high colony fragment with 3 male gonothecae in middle part, with only the perisarc left; off New Caledonia, stn DW4672; 22°47′ S, 167°26′ E; 310– 290 m; 13 Aug. 2016; KANACONO leg.; MNHN-IK-2015-360 • originally a 1.8 cm high colony fragment bearing a 2.2 cm long side branch, the latter carrying 2 female gonothecae; off New Caledonia, stn DW4670; 22°58′ S, 167°24′ E; 680– 612 m; 12 Aug. 2016; KANACONO leg.; a 0.8 cm long fragment of the main axis was cut off for DNA extraction, DNA 1348; voucher MHNG-INVE-120782 ; barcode identifier MK073080; MNHN-IK- 2015 -363 .

Remarks

The hydrothecae are closer to one another in this species than in C. decussata and, as stated by Galea (2015 a), their adaxial wall is comparatively shorter, these two characters readily distinguishing them. Like the previous species, C. microgona also appears sexually dimorphic and forming monoecious colonies. Its specific name is obviously inappropriate, as the hydroid was originally described based on specimens provided with ‘small’, saccular gonothecae that were not recognized then as being male. The female gonothecae are similar to those described in C. decussata (see above), but are of comparatively larger proportions (ca 6890 µm long and 3715 µm wide, when seen laterally; one gonotheca measured).

Distribution

Only known from off New Caledonia ( Galea 2015 a; present study).

Figures

Fig. 1. A–B. Caledoniana decussata Galea, 2015, female (MNHN-IK-2015-361) and male (MNHN- IK-2015-362), gonothecae. — C. Caledoniana microgona Galea, 2015, female gonotheca arising from below base of hydrotheca (MNHN-IK-2015-363). Scale bar: 1 mm.