Corhiza pauciarmata Ansín Agís et al., 2009

Galea, Horia R. & Maggioni, Davide, 2020, Plumularioid 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 708, pp. 1-58 : 34

Corhiza pauciarmata Ansín Agís et al., 2009

Figs 11D , 14 E–J; Table 7

Corhiza pauciarmata Ansín Agís et al., 2009: 56 , fig. 11.

Material examined

PACIFIC OCEAN • 2 sterile colonies, 6 and 9 cm high, respectively, with only remains of hydrorhiza; off New Caledonia, stn DW4741; 22°52′ S, 167°41′ E; 210– 210 m; 23 Aug. 2016; KANACONO leg.; barcode identifier MT655153 ; MNHN-IK-2015-604 .

Description

Colonies upright, up to 9 cm high, with strongly fascicled stems, ca 4 mm thick basally, most probably arising from rhizoid stolons. Cladia numerous, up to 1.2 cm long, given off irregularly from component tubes of stem; transverse constriction short distance above origin; proximal part ahydrothecate, with few occasional transverse nodes or signs of breakage and subsequent regeneration, with row of frontal nematothecae, distally ending in oblique node; remainder of stem heteromerously segmented, with alternating thecate and ahydrothecate internodes, both short. Thecate internodes, up to 12 per cladium, barely accommodating a hydrotheca and its 3 associated nematothecae: a mesial one and pair of laterals; mesial nematotheca immovable, with rim of upper chamber lowered adaxially; lateral nematothecae borne on short apophyses, with globular upper chamber whose abaxial wall is deeply scooped, adopting marked sinusoid shape adaxially. Athecate internodes with two frontal nematothecae in row; upper chamber with rim distinctly emarginated on adaxial side, often sinusoid. Gonothecae absent. Cnidome composed of three types of heteronemes: 1) seed-shaped, (4.8–5.1) × (3.1–3.3) µm; 2) banana-shaped, (6.4–6.6) ×(2.5–2.6) µm; 3) elongated-ovoid, (20.9–23.1) ×(4.6–5.1) µm.

Remarks

Although the ahydrothecate internodes of cladia are comparatively shorter, no other differences could be noted with the specimens described and illustrated by Ansín Agís et al. (2009).

Distribution

Scattered records from off New Caledonia ( Ansín Agís et al. 2009; present study).

Figures

Fig. 11. A. Antennella aff. varians (Billard, 1911), colony, MNHN-IK-2015-603. — B. Corhiza megatheca (Ansín Agís et al., 2009), colony, MNHN-IK-2015-600. — C. Corhiza patula Galea sp. nov., holotype colony, MNHN-IK-2015-602. — D. Corhiza pauciarmata Ansín Agís et al., 2009, colony, MNHN-IK-2015-604. Scale bars: 1 cm.

Fig. 14 (opposite page). A–D. Corhiza patula Galea sp. nov., from holotype MNHN-IK-2015-602, proximal portion of cladium (A); nematothecae: mesial (B), lateral (C), and from ahydrothecate internode (D). — E–J. Corhiza pauciarmata Ansín Agís et al., 2009, from sample MNHN-IK-2015-604, portion of cladium (E); nematothecae: mesial (F), lateral (G) and from ahydrothecate internode in lateral (H) and adaxial (I) aspects; cnidome (J). — K. Halopteris campanula (Busk, 1852), portion of cladium from sample MNHN-IK-2015-597. — L–M. Halopteris infundibulum Vervoort, 1966, cladial hydrotheca in lateral (L) and frontal (M) aspects, both from sample MNHN-IK-2015-608. — N–P. Halopteris peculiaris Billard, 1913, proximal portion of cladium seen laterally (N); single (O) or paired (P) lateral nematothecae associated to cauline hydrothecae; all from sample MNHN-IK-2015-609. Scale bars: A, E = 500 µm; B–D, F–I, O–P = 100 µm; J = 10 µm; K–N = 300 µm