The Chirostylidae of southern Australia (Crustacea: Decapoda: Anomura)
Author
Ahyong, Shane T.
Author
Poore, Gary C. B.
text
Zootaxa
2004
2004-02-18
436
1
1
88
https://www.biotaxa.org/Zootaxa/article/view/zootaxa.436.1.1
journal article
4865
10.11646/zootaxa.436.1.1
da216df7-8367-4c95-9678-f89e694af9b2
11755334
5028297
305EE123-4D3A-4AFA-B760-C7CE276424B1
Uroptychus babai
n. sp.
(
Fig. 4
)
Uroptychus granulatus
.–
Baba, 1990: 923
, 943–944, fig. 9 [not
U. granulatus
Benedict, 1902
].
Type material.
HOLOTYPE
:
AM
P26782, male (
14.1 mm
), E of
Broken Bay
,
New South Wales
, 33°31–34’S, 152°02–04’E,
905–914 m
, demersal trawl, K772307,
6 Dec 1977
.
PARATYPES
:
AM
P67834,
1 male
(
15.5 mm
),
1 female
(
16.5 mm
), off
Newcastle
,
32°49.3’S
,
152°49.1’E
,
951–1150 m
,
NZOI
U223
,
RV
Tangaroa
, R. Springthorpe & W. Ponder
,
10 Oct 1982
;
AM
P53248,
1 male
(
18.2 mm
),
1 female
(
15.4 mm
),
E of Broken Bay
,
New South Wales
, 33°28–31’S, 152°12–14’E,
951–1006 m
, demersal trawl, K8115 03,
3 Nov 1983
;
AM
P65883,
2
ovigerous females (
16.8–18.2 mm
),
E of Shoalhaven Bight
,
New South Wales
,
34°54’S
,
151°17’E
,
1115–1152 m
, K831802,
30 Nov 1983
;
NMV
J17065
,
1 male
(13.0 mm),
1 female
(
17.3 mm
), off
Nowra
,
New South Wales
,
35°00.00’S
,
151°16.30’E
,
1100 m
,
SLOPE 9
,
5
m otter trawl, M.
Gomon
et al
.,
15 Jul 1986
;
AM
P65832,
1 female
(17.0 mm),
E of Ulladulla
,
New South Wales
,
35°27’S
,
150°55’E
,
987–1025 m
, on crinoid
Glyptometra inaequalis
(
AM
J18867
), K831402,
25 Oct 1983
.
Diagnosis.
Carapace excluding rostrum slightly broader than long; lateral margins irregular, crenulate, distinctly convex, broadest posterior to midlength; with distinct, anteriorly directed anterolateral spine; posterior quarter with low ridge. Rostrum sharply triangular; dorsum unarmed. Sternite 3 anterior margin with broad Vshaped emargination. Basal antennal segment with distinct outer spine; ultimate and penultimate segments unarmed. Antennal scale extending beyond apex of ultimate peduncle segment. Pereopods 2–4 propodi not broadened distally, with 1 or 2 movable spines on lower distal margin; dactyli lined with 15–20 small, closeset, obliquely inclined spines on flexor margin, penultimate markedly broader than others.
Description.
Carapace
: Slightly broader than length (excluding rostrum). Lateral margins irregular, crenulate, distinctly convex, broadest posterior to midlength; with distinct, anteriorly directed anterolateral spine; posterior quarter with low ridge. Rostrum sharply triangular, about half length of remaining carapace, margins unarmed; dorsum sparsely setose or naked. Outer orbital angle produced to triangular tooth, not extending beyond anterolateral spine. Dorsum carapace sparselysetose, unarmed. Pterygostomian flap with triangular anterior spine.
Sternum
: Plastron about as broad as long, slightly widening posteriorly. Sternite 3 (at base of maxilliped 3) not depressed, anterior margin with broad Vshaped emargination; outer lobes of emargination obtusely angled, flanked by short projection. Sternite 4 (at base of pereopod 1) with obtuse anterolateral margin, extending anteriorly to about midlength of emargination of sternite 3.
Abdomen
: Segments sparsely setose. Telson about half as long as broad; distal portion posteriorly emarginate, about 1.5 times length of proximal portion.
FIGURE 4.
Uroptychus babai
n. sp.
, holotype male, 14.1 mm, AM P26782. A, dorsum. B, anterior carapace, right lateral. C, cheliped merus, proximal right ventral. D, telson. E, sternum. F, maxilliped 3, right lateral. G, crista dentata, right. H, antenna, right ventral. Scale A–C = 4 mm, D–F = 2 mm, G–H = 1 mm.
Eye
: Cornea not dilated, about onethird length of peduncle; not reaching to proximal half of rostrum.
Antenna
: Basal segment with distinct outer spine. Flagellum about twice as long as peduncle. Ultimate and penultimate segments unarmed; ultimate segment about twice length of penultimate segment. Antennal scale wider than opposite peduncular segments, extending beyond apex of ultimate peduncle segment.
Maxilliped 3
: Dactylus, propodus, carpus and merus unarmed. Crista dentata evenly serrate on proximal threequarters of ischium, not extending onto basis.
Pereopod 1 (cheliped)
: Slender, rugose with setose scales, subcylindrical; about 3 times carapace length. Propodus with palm about 3.5 times as long as high, about twice as long as pollex. Fingers crossing, occlusal margins finely dentate; occlusal margin of dactylus with obtuse process proximally; occlusal margin of pollex with low prominence at midlength. Carpus longer than merus and as long as propodal palm. Ischium with triangular spine on outer margin.
Pereopods 2–4
: Setose, similar, becoming shorter distally. Carpi and meri unarmed. Propodi not broadened distally, with 1 or 2 movable spines on distal flexor margin. Dactyli lined with 15–20 small, closeset, obliquely inclined, fixed spines on flexor margin, penultimate markedly broader than others. Carpus of pereopods 2–3 about 0.4 merus and 0.5 propodus length; carpus of pereopod 4 about 0.5 merus length, about 0.4 propodus length.
Ovum
:
1.3 mm
diameter.
Etymology.
Named for Keiji Baba,
Kumamoto
University,
Japan
, for his foundational work on the systematics of the Galatheidea.
Remarks.
Uroptychus babai
n. sp.
closely resembles
U. granulatus
Benedict, 1902
, from the Galapagos Islands. The two species agree in almost all respects, but
U. babai
differs in having crenulate or irregular instead of spinose lateral carapace margins, the basal antennal segment bears a distinct outer spine, a short median notch is present in the anterior concavity of sternite 3 and the anterolateral angles of sternite 4 are bluntly rounded instead of acute.
Baba (1990)
reported and figured material identified as
U. granulatus
from
Madagascar
in which the lateral carapace margins are irregular or crenulate but not spinose as in the
holotype
from the Galapagos Islands. Based on
Baba’s (1990)
account, the specimens from
Madagascar
are referable to
U. babai
, and significantly extend the range of the species.
Uroptychus babai
also resembles
U. bacillimanus
Alcock & Anderson, 1899
, and
U. valdiviae
Doflein & Balss, 1913
, both from the eastern Indian Ocean, in the shape of the carapace, and limb proportions.
Uropotychus
babai
is readily distinguished from
U. bacillimanus
in having welldeveloped instead of minute anterolateral spines on the carapace and in having the antennal scale longer instead of distinctly shorter than the antennal peduncle. The strong anterolateral spine and welldeveloped outer orbital spine of the carapace will readily distinguish
U. babai
from
U. valdiviae
.
Of the regional
Uroptychus
species
,
U. babai
resembles two
New Zealand
species,
U. maori
Borradaile, 1916
, and
U. tomentosus
Baba, 1974
, in carapace shape and overall habitus.
Uroptychus babai
is readily distinguished from
U. tomentosus
in the length of the antennal scale (longer than instead of shorter than the antennal peduncle) and in having a small triangular tooth instead of long falcate spine on the dorsal distal margin of the ischium of the cheliped.
Uroptychus babai
chiefly differs from
U. maori
in the length of the antennal scale (longer than instead of distinctly shorter than the antennal peduncle), in lacking an inner distal spine on the penultimate antennal peduncle segment, and in having 15–17 instead of 6 spines on the flexor margin of the dactyli of pereopods 2–4.
Distribution.
Southeastern
Australia
at depths between 905 and
1150 m
, and
Madagascar
at
880–920 m
(
Baba, 1990
).