Klugella rufula, Hayward & Winston, 2011

Hayward, Peter J. & Winston, Judith E., 2011, Bryozoa collected by the United States Antarctic Research Program: new taxa and new records, Journal of Natural History 45 (37 - 38), pp. 2259-2338 : 2263-2265

Family BUGULIDAE Gray, 1848

Klugella rufula sp. nov.

( Figure 2 )

Material

Holotype. NMNH 11540038 : Eltanin cruise 22, station 1536, 54 ◦ 29’ to 54 ◦ 31’S, 39 ◦ 22’ to 39 ◦ 19’ W, 659–686 m, 8 February 1966; a single large colony in>10 fragments, the largest 4.5 cm high . Paratype: VMNH 013675.00, same data as Holotype .

Description

Colony erect, branching dichotomously, lightly calcified and flexible, consisting of flat, strap-like unilaminar fronds, 1.25–2.5 mm wide, broadest before dichotomy; in alcohol retains a reddish brown coloration. Autozooids in six alternating longitudinal series, halving at dichotomy, increasing again to six within two or three generations beyond. Autozooids elongate, in frontal view four times as long as wide, each arising from the abfrontal surface of its predecessor as a deeply forked fishtail, the distal half projecting from the branch frontal plane. Frontal surface of autozooid almost entirely membranous, the very thinly calcified lateral walls converging frontally just above the fishtail origin of the autozooid. Autozooids asymmetrical in frontal view: distal end truncate, sloping away to margin of branch on left and right of the midline; spines similarly asymmetrical, typically one at each distal corner, then 10–12 along the outer marginal rim of the autozooid, and only three or four along the inner, axial border of the zooid. Lateral walls of autozooids with large rosette plates, four pores per plate, in a single linear series. Avicularia very sparse, apparently budded from abfrontal surface of zooid, projecting medially above frontal membrane of next zooid; shortly pedunculate, clavate, with a terminal, semicircular mandible. No ovicells observed. The colony is attached by bundles of tubular rhizoids. These appear to bud from septula along marginal zooids of the branch, they pass proximally, closely applied to marginal abfrontal surfaces and then over entire abfrontal surface, very closely applied, and then divide terminally. The rhizoids are septate and seem to divide dichotomously at intervals.

Measurements

Autozooid length (of spine-bearing margin, n = 20) 1.30 ± 0.18 mm (mean ± SD); autozooid width (distal width between second spine pair, n = 20) 0.30 ± 0.02 mm.

Etymology

Latin, rufus: reddish

Remarks

Two other species of Klugella are known, Klugella echinata ( Kluge, 1914) , which appears to be an Antarctic endemic, and Klugella buski Hastings, 1943 , which is known only from Kerguelen. Klugella rufula sp. nov. is similar to K. echinata in its unilaminar colony form but has much narrower branches, those of the latter being up to 10 mm wide. Further, the autozooids of K. echinata are quite symmetrical, although the marginal spines are asymmetrically distributed, and the avicularia are stout and broadly pedunculate, with an elongate, almost setiform mandible. Klugella buski has just one or two pairs of short, inconspicuous spines at the distal end of the autozooid, and the sparsely distributed avicularia have long, triangular mandibles.

Figures

Figure 2. Klugella rufula sp. nov., Holotype. (A) Part of a branch; (B) linear series of autozooids in medial view, to show multiporous septula; (C) branch dichotomy in basal view. Scale bars: 0.25 mm (A, B), 0.5 mm (C).