Plumularia bathyalis, Agís & Vervoort & Ramil, 2014

Agís, José Ansín, Vervoort, Willem & Ramil, Fran, 2014, Hydroids of the families Kirchenpaueriidae Stechow, 1921 and Plumulariidae McCrady, 1859 (Cnidaria, Hydrozoa) collected in the Western Pacific Ocean by various French Expeditions, Zoosystema 36 (4), pp. 789-840 : 798-800

publication ID 10.5252/z2014n4a6

persistent identifier

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scientific name

Plumularia bathyalis

n. sp.

Plumularia bathyalis   n. sp.

( Fig. 5 View FIG ; Table 5)

MATERIAL EXAMINED. — New Caledonia. BIOGEO- CAL, stn DW 313, 20°58.95’-20°858.97’S, 166°59.04’- 166°59.30’E, 1600-1640 m, 02. V.1987: single 35 mm high colony in two parts, no gonothecae, holotype (MNHN-IK-2012-14252).

ETYMOLOGY. — The specific name bathyalis   , from the Greek “bathos = deep”, refers to the bathyal region, where the species was collected.

DISTRIBUTION. — Only known from New Caledonia (type locality) at 1600-1640 m depth.


Colony plumose, unbranched, polysiphonic in basal part.

Hydrorhiza composed of tubules probably anchoring the colony in soft bottoms.

Stem irregularly divided by transverse nodes, slightly visible only in apical part of colony, with apophyses alternately directed left and right. Each apophysis with a well developed mamelon on superior surface, two axillary nematothecae and occasionally an imperfect perisarc ring at distal end. Main axis with two nematothecae between every two successive apophyses.

Hydrocladia, inserted on apophyses, composed by a succession of athecate and thecate internodes separated by straight nodes. Thecate internodes with one hydrotheca and three nematothecae: one mesial inferior and two lateral. Hydrotheca placed in middle of internode, deep, conical, narrowing towards base, adcauline wall fully adnate and with a small projection in the middle part; abcauline wall straight, rim smooth. Mesial nematotheca placed on a distinct swelling close to the basal node. Lateral nematothecae born below and projecting above hydrothecal rim. Athecate internodes with one nematotheca on a distinct swelling proximal to the basal node. All nematothecae conical, bithalamic and movable.

Gonothecae absent.

MUSORSTOM 4 stn CP 178

Height of colony (in mm) 150

Stem internode, length Variable

Length thecate hydrocladial 580-640


Diameter at node 65-80


Length abcauline wall 310-350

Length adcauline wall 210-250

Diameter at rim 75-100

Mesial nematotheca, length 65-70

Diameter at rim 20-30

Lateral nematotheca, length 60-85

Diameter at rim 20-30

Supracalycine nematotheca, length 60-70

Diameter at rim 20-30


The first thecate internode of hydrocladia usually bears two mesial inferior nematothecae: one near the basal node and other below the hydrotheca but with its margin reaching the base. Only the basal nematothecae is placed on a distinct swelling. Rest of thecate internodes with only one mesial inferior nematotheca, except in cases of damage and further regeneration where two nematothecae are possible.


The species is characterized by having deep hydrothecae and by the development of a shallow projection on the adcauline wall of the hydrothecae.


Royal British Columbia Museum - Herbarium