A new asterinid genus from the Indo-West Pacific region, including five new species (Echinodermata: Asteroidea: Asterinidae)
Author
O'Loughlin, P. Mark
Author
Rowe, Francis W. E.
text
Memoirs of Museum Victoria
2005
2005-12-31
62
2
181
189
https://museumsvictoria.com.au/collections-research/journals/memoirs-of-museum-victoria/volume-62-issue-2-2005/pages-181-189/
journal article
10.24199/j.mmv.2005.62.6
1447-2554
12208000
Ailsastra
gen. nov.
Figure 1
Type
species.
Ailsastra paulayi
sp. nov.
Other included species.
Ailsastra achituvi
sp. nov.
;
A. amezianeae
sp. nov.
;
A. booneni
sp. nov.
;
A. eleaumei
sp. nov.
;
Asterina heteractis
H.L.
Clark, 1938
.
Diagnosis
.
Small, stellate asterinids, up to
R
=
16 mm
; rays predominantly 5; one species fissiparous (5–7 rays); interradial margin incurved, rays discrete, broad to narrow at base, short to long, rounded distally; flat actinally, convex abactinally, inferomarginal plates project to form acute ventrolateral margin; disc distinctly to irregularly defined; carinal series of plates present for most of ray, doubly papulate with 2 longitudinal series of large papulae for most of ray, each plate with rounded anterior projection; carinal plates imbricated by adcarinal plates on both sides, forming characteristic ‘sunken’ series; other abactinal plates closely imbricate, not notched, arched over papular space more than indented proximally for papula; lacking secondary plates; papulae on rays single per papular space, large, in longitudinal series; spinelets glassy, thick to thin, conical or sacciform or subsacciform, pointed or splay-pointed, in clusters or single or double series across proximal plates, sometimes in round or oval bowl-shaped series on plate; lacking pedicellariae with differentiated valves; plates with prominent glassy convexities; superomarginal and inferomarginal plates in regular series; actinal interradial plates in predominantly oblique series; oral plates distinctively small, constricted distally (pair with form of short-handled, smooth-headed mace or club); oral spines up to 6, series incurved distally; suboral spines variably present, if present in continuous series with distal oral spines; lacking superambulacral and superactinal plates in
type
species and two other investigated species
.
Distribution
. Lord Howe I., NE
Australia
, Sulawesi I., Sudanese Red Sea,
Mauritius
, NW
Madagascar
; rock and coral;
0–
16 m
.
Etymology
. From
Ailsa
with the Latin
astrum
(star), in recognition of the substantial contribution by Ailsa Clark to seastar systematics (feminine).
Remarks
. Superambulacral and superactinal plates are absent from the
type
species
A. paulayi
, and
A. amezianeae
and
A. eleaumei
. The remaining three species (which have not been dissected) have the other generic characters of
Ailsastra
, and it is anticipated that they too lack these internal plates.
Ailsastra
shares the lack of superambulacral and superactinal plates with seven other genera currently included in the
Asterinidae
:
Asterina
,
Asterinides
,
Kampylaster
,
Meridiastra
,
Pseudasterina
,
Pseudopatiria
and
Tremaster
(see
O’Loughlin and Waters, 2004
). However, the form of the oral plates and arrangement of the carinal series of plates distinguish
Ailsastra
, morphologically, from these and all other genera in the family. The morphological justification for recognising the new genus is supported by limited molecular data that places the
two specimens
of the type-species
A. paulayi
sp. nov.
(see below) in a highly divergent but strongly monophyletic clade within a molecular phylogeny of
Asterinidae
(Jon Waters, pers. comm.; paper in preparation).