Chirostylidae of the Western and Central Pacific: Uroptychus and a new genus (Crustacea: Decapoda: Anomura)
Author
Baba, Keiji
Kumamoto University Faculty of Education 2 - 40 - 1 Kurokami Kumamoto 860 - 8555 Japan kbaba. kumamoto @ gmail. com
kbaba.kumamoto@gmail.com
text
Mémoires du Muséum national d'Histoire naturelle
2018
2018-09-30
Tropical Deep-Sea Benthos
212
1
612
journal article
22904
10.5281/zenodo.3760976
aaaa853e-f89e-4090-81d4-a4406eebfc53
978-2-85653-822-7
1243-4442
3760976
Uroptychus joloensis
Van Dam, 1939
Figure 305
E-G
Uroptychus joloensis
Van Dam, 1939: 395
,figs 2, 2a,2b, 2c. —
Ahyong & Baba 2004: 58
, fig.1. —
Baba 2005:39
, 227.—
Baba
et al.
2008: 35
. —
Poore
et al.
2011: 328, pl. 6, fig. I. —
McCallum & Poore 2013: 164
, fig. 12D.
Uroptychus kudayagi
Miyake, 1961: 237
, figs 1, 2. — 1982: 143, pl. 48, fig. 2. — Minemizu 2000: 165,unnumbered fig. — Kawamoto & Okuno 2003:
97, unnumbered fig.
TYPE MATERIAL
—
Holotype
:
Philippines
,
Jolo Sea
, 37.8-56.7 mn male (
ZMUC
). [not examined].
MATERIAL EXAMINED
—
Philippines
. MUSORSTOM 1 Stn CP60, 14°05’N, 120°19’E, 129-124 m, 27.III.1976, 1 ♂ 4.9 mm, 1 ov. ♀ 4.5 mm (MNHN-IU-2014-16585)
.
MUSORSTOM 3 Stn CP134,12°01’N, 121°57’E,92-95 m, 5.VI.1985, 1 ♂ 3.3 mm (MNHN-IU-2014-16586)
.
Solomon Islands
.
SALOMON
1 Stn CP1831, 10°12.1’S, 161°19.2’E, 135-325 m, 5.X.2001, 1 ♂ 2.7 mm (MNHN-IU-2014-16587)
.
Vanuatu
. GEMINI Stn DW48, 21°00’S, 170°04’E, 200-150 m, 04.VII.1989, 1 ♂ 2.5 mm, 1 ov. ♀ 3.1 mm (MNHN-IU-2014-16588)
.
MUSORSTOM
8
Stn CP1131, 15°38.41’S, 167°03.52’E, 140-175 m, 11.X.1994, 1 ♂ 3.0 mm (MNHN-IU-2014-16589)
;
2 ov. ♀ 2.9, 3.0 mm (MNHN-IU-2014-16590)
.
– Stn CP1133, 15°38.83’S, 167°03.06’E, 174-210 m, 11.X.1994, 1 ♀ 2.8 mm (MNHN-IU-2014-16591)
.
– Stn CP1077, 16°04.00’S, 167°06.09’E, 180-210 m, 5.X.1994, 1 ♂ 2.7 mm (MNHN- IU-2014-16592)
.
– Stn CP1071, 15°36.63’S, 167°16.34’E, 180-191 m, 4.X.1994, 1 ♂ 3.3 mm (MNHN-IU-2014-16593)
.
– Stn CP961, 20°18.50’S, 169°49.90’E, 100-110 m, 21.IX.1994, 1 ov. ♀ 3.2 mm, 1 ♀ 2.0 mm (MNHN-IU-2014-16594)
.
Santo Stn AT04, 15°32.9’S, 167°13.3’E, 97-101 m, 15.IX.2006, 1 ov. ♀ 3.0 mm (MNHN-IU-2014-16595)
.
– Stn AT06, 15°38’S, 167°02’E, 140-167 m, 15.IX.2006, 1 ♂ 3.5 mm, 2 ov. ♀ 3.2, 3.8 mm, 1 ♀ 3.2 mm (MNHN-IU-2014-16596)
.
– Stn AT17, 15°40’S, 167°02’E, 267-270 m, 21.IX.2006, 1 ♂ 3.2 mm (MNHN-IU-2014-16597)
.
–
Stn
AT22,
15°32.3’S
,
167°16.0’E
,
180-227 m
,
22.IX.2006
, 1 ov.
♀
3.7 mm
(
MNHN-IU-2014-16598
).
Wallis and Futuna
Islands. MUSORSTOM 7 CP498,
14°19’S
,
178°03’W
105-160 m
,
10.V.1992
, on
Chironephthya
sp. (
Nidaliidae
:
Alcyonacea
), 4 ov.
♀
2.5-2.8 mm
(MNHN-IU-2014-16599, MNHN-IU-2014-16600,
MNHN-
IU-2014-16601, MNHN-IU-2014-16602
).
Fiji Islands
. MUSORSTOM 10 CP1364,
18°11.9’S
,
178°34.5’E
,
80-86 m
,
15.VIII.1998
, 1 ov.
♀
3.2 mm
(
MNHN-
IU-2014-16603)
.
DISTRIBUTION„
Previously known from Jolo Sea, Kai Islands, Timor Sea and northwestern
Australia
in
37.8-142 m
; and under the name
U. kudayagi
Miyake, 1961
, from
Japan
(eastern Sagami Bay, west coast of Kyushu, southern Kii Peninsula,
Shizuoka
, and
Okinawa
), in
20-
80 m
. The present material was taken from the
Philippines
,
Solomon Islands
,
Vanuatu
,
Wallis and Futuna
Islands, and
Fiji Islands
, in
80-
325 m
. Additional material was collected from the southern coast of
Papua New Guinea
, in
25 m
(see below under the remarks).
SIZE„
Males,
2.7-4.9 mm
; females 2.0-
4.5 mm
; ovigerous females from
2.5 mm
.
DIAGNOSIS
— Small species. Carapace smooth on surface, somewhat broader than long, greatest breadth about twice distance between anterolateral spines. Lateral margins feebly convexly divergent posteriorly; anterolateral spine situated closely lateral to and overreaching smaller lateral orbital spine; 2 spines about at anterior third (anterior one occasionally very small, vestigial or even obsolete, posterior one larger), followed by ridge along remaining margin. Rostrum triangular, with interior angle of 22-25°, lateral margin with small spine often obsolete, dorsal surface concave, breadth less than half carapace breadth at posterior carapace margin. Pterygostomian flap anteriorly angular, ending in sharp spine. Excavated sternum anteriorly subtriangular, with cristate ridge in midline; sternal plastron slightly longer than broad, with subparallel lateral extremities; sternite 3 having anterior margin very weakly concave, with deep median sinus usually U-shaped, flanked by small incurved spine; sternite 4 with anterolateral margin 1.5 × length of posterolateral margin; anterolateral margins of sternite 5 slightly convexly subparallel, slightly longer than posterolateral margin of sternite 4. Abdominal somite 1 without transverse ridge; somite 2 tergite 2.2-2.4 × broader than long; pleural lateral margins feebly or somewhat concave, subparallel or somewhat divergent posteriorly, posteriorly blunt; pleuron of somite 3 laterally rounded. Telson about half as long as broad; posterior plate 1.4-1.8 × longer than anterior plate, posterior margin roundish. Eyes elongate, distally narrowed, barely reaching apex of rostrum. Ultimate antennular article 2.5 × longer than high. Article 2 of antenna with sharp lateral spine; antennal scale terminating in midlength of article 5; articles 4 and 5 each with distinct distoventral spine, article 5 1.2-1.4 × longer than article 4, breadth 0.6-0.7 × height of ultimate antennular article; flagellum of 6-9 segments not reaching distal end of P1 merus. Mxp1 with bases separated from each other. Mxp3 sharply ridged along flexor margins of ischium and merus; basis with obsolescent denticles on proximal part of mesial ridge; ischium with small spine lateral to rounded distal end of flexor margin, crista dentata with obsolescent denticles; merus about twice longer than ischium, with distolateral spine and 1 or 2 small spines distal to midlength of flexor margin; carpus with distolateral spine and often with small spine on proximal lateral surface. P1 slender, subcylindrical, bearing soft fine setae; 6.2-6.4 × (males), 5.7-7.0 × (females) longer than carapace; ischium dorsally with 2 spines (distal one well-developed and sharp, proximal one small), ventromesially with short, blunt subterminal spine; merus 1.3-1.4 × longer than carapace, with a few small spines on mesio-proximal part of ventral surface; carpus 1.3-1.4 × longer than merus; palm subequal to or slightly longer than carpus; fingers slightly incurved; movable finger 0.3-0.4 × length of palm. P2-4 well compressed mesio-laterally; meri subequal in breadth on P2-4; P2 merus 0.8-0.9 × length of carapace, 1.1-1.2 × length of P2 propodus; P3 merus 0.9 × length of P2 merus, 0.9 × length of P3 propodus; P4 merus 0.9-1.0 × length of P3 merus, 0.8 × length of P4 propodus; carpi subequal, each less than half length of propodus; propodal flexor margin with pair of distal spines only; dactyli longer than carpi (dactyluscarpus length ratio, 1.0-1.1 on P2, 1.1-1.2 on P3, 1.2 on P4), flexor margin with 6 or 7 loosely arranged spines, ultimate slender, penultimate, antepenultimate and often distal quarter prominent, remaining 2 or 3 diminishing proximally, proximal-most somewhat inclined.
Eggs.
Number of eggs carried up to 18; size,
0.65 mm
×
0.69 mm
-
0.9 mm
×
1.1 mm
.
COLOR
— Base color translucent white, reddish on anterior part of carapace (around rostrum, including antennule and antenna) and around juncture between P1 palm and fingers (ov.
♀
3.0 mm, MNHN-IU-2014-16595 [=
Poore
et al.
2011
: pl. 6, fig. I]); additional red spot at juncture between P1 merus and carpus (specimens from
Papua New Guinea
, see below under the remarks); red spot absent from P1 (ov.
♀
, MNHN-IU-2014-16602;
McCallum & Poore, 2013
: fig. 12D).
REMARKS
— The species is characterized by the carapace lateral margin with two spines about at distal third (the distal of which is often obsolete), the antennal articles 4 and 5 each bearing a strong distal spine, the antennal scale barely reaching the end of the antennal article 5 (usually terminating in the midlength of this article) and the eyes distally narrowed. As noted by
Baba
et al
. (2009)
,
Uroptychus joloensis
resembles
U. zezuensis
in morphology, coloration and habitat preference (see below under
U. zezuensis
).
The material reported under
U. kudayagi
from
Japan
(Miyake 1961, 1982; Minemizu 2000; Kawamoto & Okuno 2003) bears red spots at junctures between the P1 merus and carpus, and between the palm and fingers, in addition to another red spot around eyes including the rostrum. Specimens identical with this material (
1 male
2.3 mm
, 1 ov. female
2.1 mm
,
2 eggs
0.82 ×
0.86 mm
, QM W25105), taken at
25 m
, Bootless Bay,
Port Moresby
,
Papua New Guinea
, were made available, along with a photograph through Peter J.F. Davie (
Figure 305G
). On the other hand, the spots on P1 are totally absent in one of the specimens from the
Wallis and Futuna
Islands (MNHN-IU-2014-16602) as well as in the specimen from Western Australia (
McCallum & Poore 2013
: fig. 12D). The specimen from
Vanuatu
(MNHN-IU-2014-16595) has the spot only between the palm and fingers (
Poore
et al.
2011
: pl. 6, fig. I). Inasmuch as no morphological differences are found between all of these forms of different color, these are treated as identical. However, it is not unlikely that the color differences may be validated for species discrimination by molecular data, as has been done for some species of
Galathea
(
Macpherson & Robainas-Barcia 2015
)
.
According to Minemizu (2000) and Kawamoto & Okuno (2003), this species is found among branches of alcyonacean corals, usually
Siphonogorgia dofleini
,
rarely
S. dispacea
(Nidaliidae)
. The red spots of the animal resemble the color pattern of the host’s polyps. One of the specimens from MUSORSTOM 7 Stn CP498 (MNHN-IU-2014-16601) was found on
Chironephthya
sp. (
Nidaliidae
).