Holotype: NMV F101702, fertile colony of 10 stems, Middle Island, Recherche archipelago, Western Australia, depth 15 m, on sponge on vertical wall.
The carinate median cusp of the hydrotheca is reminiscent of that of Aglaophenia laxa Allman, 1876, but Aglaophenia recherchia is readily distinguished from that species by the twin terminal apertures of the median nematotheca.
The species is named for the type locality of the Archipelago of the Recherche, Western Australia
Hydrorhiza deeply embedded in sponge; stems short, to 30 mm long, rather thick and lightly fascicled, polysiphonic tubes twisted and deeply internally corrugated in proximal region, becoming fewer and more or less parallel further up stem; tubes ending in a deep V-shaped flexion joint below proximal hydrocladium. Stems branched in one to three orders, branches to 10 mm long, recurved, irregularly distributed around stem or on one side only, opposite to alternate, proximal part of branch usually monosiphonic, with three to 10 ahydrocladiate internodes but sometimes lightly fascicled, polysiphonic tubes running along proximal branch to a long blade-shaped flexion joint; branch thereafter monosiphonic and hydrocladiate; internodes short, wide, nodes oblique, distinct, perisarc thick and corrugated internally between nodes.
Hydrocladia alternate, crowded, one per stem internode, given off one above other at an acute angle from a short frontal apophysis; hydrocladial internodes short, deep, nodes thick, slightly oblique; two broad, complete intranodal septa, one directed slightly backward from below intrathecal septum, the other directed slightly forward from posterior of lateral nematotheca; perisarc along base of hydrocladium thick.
Hydrothecae seated on top of internode, crowded, semi-ovoid, upright, divided into posterior and anterior chambers by a thick intrathecal septum passing through body from floor to abcauline wall; septum typically concave, upper part parallel with inner wall of median nematotheca, floor of septum opening into a foramen connecting with hydrocladial septum. Margin of hydrotheca complexly cuspate; anterior cusp large, hatchet-shaped with a circular foramen at base connecting with base of median nematotheca, this followed (lateral view) by five pairs of deeply incised cusps, the first pair blunt, second pair of similar height but narrower and more pointed, third pair blunt, overlapping second pair, next pair larger, blunt, posterior pair blunt. In anterior view, median cusp long, tongue-shaped, first pair bent outwards, following pairs alternately bent inwards and outwards, second and third pair and fourth and fifth pair conjoined at base.
Median nematotheca robust, variable in length along hydrocladium, shorter proximally, becoming progressively longer to twice height of hydrotheca at mid-region of hydrocladium then shortening again distally along hydrocladium; nematotheca following curve of hydrotheca to end of intrathecal septum then becoming upright, curved; abcauline wall very thick, apex with a pair of small circular apertures separated by a shallow notch, a secondary orifice extending from about halfway down free wall to hydrothecal margin. Lateral nematothecae long, tubular, curved upward, narrowing from base to margin; base deeply inserted in hydrocladium with a wide internal connection with hydrocladium, terminal aperture circular, projecting beyond margin of hydrotheca, a secondary aperture facing towards hydrotheca. Cauline nematothecae same as laterals, one on internode above hydrocladium.
Corbulae long, pod-shaped, one or two on branch, gonohydrocladium with one proximal hydrotheca and short, free no; corbula open, at maturity with 18-20 close, arched ribs meeting in a zigzag pattern along summit; ribs with closely spaced opposite nematothecae on both edges; nematothecae same as laterals with terminal aperture and secondary aperture facing towards rib, a larger nematotheca at apex of each no; apex of corbula with a small curved spine with a single nematotheca.
Colour: Colony dark brown; perisarc very thick and brittle.
Subtidal, epizoic on sponges.
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