Latrunclava Kelly, Reiswig & Samaai,

Kelly, Michelle, Sim-Smith, Carina, Stone, Robert, Reiswig, Toufiek Samaai Henry & Austin, William, 2016, New taxa and arrangements within the family Latrunculiidae (Demospongiae, Poecilosclerida), Zootaxa 4121 (1), pp. 1-48: 33-34

publication ID

http://doi.org/10.11646/zootaxa.4121.1.1

publication LSID

lsid:zoobank.org:pub:2C978846-61DD-48BD-87BE-0BC22D0CABF2

persistent identifier

http://treatment.plazi.org/id/03F40C7E-FF85-2905-CCDB-FD0CFA93FE0D

treatment provided by

Plazi

scientific name

Latrunclava Kelly, Reiswig & Samaai
status

gen. nov.

Genus Latrunclava Kelly, Reiswig & Samaai  gen. nov.

Type species. Latrunclava imago  gen. et. sp. nov., designated herein.

Diagnosis. Thickly encrusting Latrunculiidae  with two microsclere forms: 1) anisodiscorhabds with manubrium, basal whorl, median whorl and apical whorl; 2) several size categories of long anisoconicorhabds, with manubrium and basal whorl, apical whorl and apex, and lightly acanthose shaft, and spines arrayed irregularly between the ends of the spicule, around the shaft. Megascleres are sinuous anisostyles, acanthose on the head. Ectosomal skeleton consists of a paratangential layer of megascleres above which is a palisade of anisodiscorhabds. The choanosome is a wispy irregular polygonal reticulation of megascleres. Anisoconicorhabds are scattered without orientation, throughout the outer choanosome, and across the ectosome.

Etymology. Named for Latrunculiidae  with a new form of sceptre that resembles a spined or knobbed cudgel (clava, knobbed club; L.)

Remarks. Species in the new genus Latrunclava  are characterised by the possession of a second form of microsclere in addition to the normal anisodiscorhabds: the sceptre-like anisoconicorhabd in several size categories, with manubrium and basal whorls, apical whorl and apex, but which lacks a median and subsidiary whorl. This form of sceptre extends between the basal whorl and apical whorl with a lightly acanthose shaft covered irregularly in sharp, single or palmate spines; the spines rarely form whorls around the shaft. All size categories of these sceptres are much longer than the ‘normal-length’ anisodiscorhabd and are scattered throughout the choanosome and ectosome without particular orientation. The anisodiscorhabds of Latrunclava  gen. nov superficially resemble those in species of Latrunculia (Uniannulata)  subgen. nov., with manubrium, basal and median whorls, and an apical whorl, but both lack a subsidiary whorl and apex.

The new genus Latrunclava  can be compared to Sceptrella  which also has a second form of sceptre-like microsclere, the isoconicorhabd (Samaai & Kelly 2002), also scattered throughout the choanosome and ectosome without orientation. The key differences are, however, the form of the sceptre (equiended in species of Sceptrella  and inequiended in the species of Latrunclava  gen. nov.), and there is usually only one size category of isoconicorhabd in Sceptrella  spp. With the exception perhaps of S. insignis ( Topsent, 1890)  , the isoconicorhabds of Sceptrella  species have basal and apical whorls of spines or serrated crowns that are virtually identical to each other; they do not, in any way, resemble an anisoconicorhabd. On the other hand, the anisoconicorhabd of Latrunclava  gen. nov. has a clear manubrium, basal whorl, apical whorl and apex, but is extended between these features by a shaft of irregularly placed spines.

The anisodiscorhabds of Latrunculia oamaruensis Hinde & Holmes, 1892  , named for several microfossil spicules in the New Zealand Late Eocene Oamaru Diatomite, also bear a general likeness to the anisoconicorhabds of Latrunclava  gen. nov. ( Fig. 12View FIGURE 12 C) in that they are also inequiended. The key difference between the spicules of Latrunclava  gen. nov. and the microfossil spicules is, however, differences in the morphology of the base of the microsclere, which in L. oamaruensis  is a blunt extension of the shaft terminating with whorls of small spines. These fossil microscleres are more strongly reminiscent of the anisodiscorhabds of L. (L.) multirotalis Topsent, 1927  and L. (L.) tetraverticillata Mothes, Campos, Eckert & Lerner, 2008  , which also have multiple whorls around the shaft, but these are plate-like.

Several other microfossil spicules that closely resemble those of L. (L.) multirotalis  and L. (L.) tetraverticillata  , have been described and illustrated by Hinde & Holmes (1892: 218; Pl. 11, Fig. 36, 37) and Bukry (1979: Pl. 6, Fig. 12View FIGURE 12, 13View FIGURE 13). Furthermore, L. apicalis Ridley & Dendy, 1886  and L. biformis Kirkpatrick, 1907  also have second, larger forms of multi-whorled or spined microscleres. Currently, L. apicalis  , L. multirotalis  , L. biformis  , and L. tetraverticillata  are placed in the subgenus Latrunculia  but the possession of a second category of microsclere is unusual enough to potentially warrant the establishment of another new subgenus in the future. Until further study can be made of these and other species in the context of Sceptrella  and Latrunclava  gen. nov., we hereby remove the four species, L. apicalis  , L. multirotalis  , L. biformis  , and L. tetraverticillata  , from the subgenus Latrunculia  ( Table 9). Figure G illustrates the diagnostic microscleres that define Latrunclava  gen. nov.