MELITHAEINAE, Alderslade, 2006

Alderslade, Philip, 2006, New subfamilies and a new genus and species of Melithaeidae (Coelenterata: Octocorallia: Alcyonacea) with comparative data on the structure of both melithaeid and subergorgiid axes, Zootaxa 1199, pp. 19-47 : 21-22

MELITHAEINAE new subfamily

Diagnosis. Melithaeids with axial sclerites in the form of short, straight rods that commonly have a median girdle of simple tubercles. Nodes generally conspicuous, even when covered in coenenchyme, and node­internode articulations relatively well delimited. Internodal sclerites longitudinally arranged and embedded in a matrix of subhedral calcite rods. Nodal sclerites each encased in a gorgonin sheath which bonds where the ends of the sclerites touch to form a relatively regular, polyhedral latticework whose multitudinous interstices are filled with mesogloea. Polyps with a well­defined collaret and points arrangement constructed from a relatively small number of large sclerites.

Type genus: Melithaea Milne Edwards & Haime, 1857 , here designated. ASPERAXINAE new subfamily

Diagnosis. Melithaeids with axial sclerites in the form of rods and sticks that are often sinuous and branched and possess simple, sparse, tubercles. Nodes whole or partial, inconspicuous when covered in coenenchyme, poorly delimited from the internodes, and soft and pale in colour owing to a low proportion of gorgonin relative to scleritic calcite. Sclerites within the internodes embedded in a matrix of subhedral calcite rods. Sclerites of the surface of the internodes (occasionally including a few coenenchymal sclerites) anastomosing and only partly embedded in the matrix, commonly forming longitudinal ridges. Outer nodal sclerites often forming continuations of the internodal ridges. Nodal sclerites each encased in a gorgonin sheath that is continuous where they come together, often in groups, forming a very irregular meshwork whose interstices are filled with mesogloea. Polyps armed with numerous small sclerites.

Type genus: Asperaxis new genus, here designated.

Asperaxis new genus

Diagnosis. Internodes with a hollow central core containing a calcareous 3­dimentional latticework surrounded by a dense, thick, calcareous wall constructed from sclerites that are partially or totally embedded in a matrix of subhedral calcite rods. Nodes full or partial, not clearly delimited from the internodes but permeating the contiguous internodal structure, and consisting of sclerites united in an organic matrix of gorgonin and mesogloea. Internodal sclerite forms composed of rods, often sinuous and branched, with simple, sparse, tubercles. Nodes containing similar sclerite forms along with small irregular rods with thickened tuberculate ends.

Polyps retractile into prominent calyces, and armed with collaret and points; the collaret poorly developed and essentially formed from the merging of the of the near­horizontal proximal point sclerites. Pinnules and tentacle rachis containing scales. Calyces and coenenchyme with rods and spindles that are ornamented with large, complex tubercles.

Colonial branching from the nodes producing small bushy colonies that may have more than one point of attachment to the substratum. Branches commonly sinuous. Nodes rarely thicker than the internodes, sometimes crowded together and many occurring at places other than points of bifurcation.

Type species. Asperaxis karenae n.sp. by original designation.

Etymology. The generic name is derived from the Latin words asper, uneven or rough, and axis alluding to the very irregular form of the colonial axis. Gender masculine.

Remarks. It is important to note that Asperaxis could be mistaken for Acabaria if the detail of the axis is overlooked.