A DISTINCTIVE NEW SPECIES OF THE DEEP-WATER SHRIMP GENUS GLYPHOCRANGON A. MILNE-EDWARDS (CRUSTACEA DECAPODA CARIDEA GLYPHOCRANGONIDAE) FROM SOUTHERN AUSTRALIA

2005·2.1 MB·English

by  Tomoyuki Komai

RecordsoftheWesternAustralianMuseum22:253-258(2005).
A distinctive new species of the deep-water shrimp genus Glyphocrangon
A. Milne-Edwards (Crustacea: Decapoda: Caridea: Glyphocrangonidae)
from southern Australia
TomoyukiKomai
NaturalHistoryMuseumandInstitute,Chiba
955-2Aoba-cho,Chuo-ku,Chiba260-8682,Japan
E-mail:[email protected]
Abstract - A distinctive new species of glyphocrangonid shrimp,
Glyphocrangon elephas, is described on thebasis ofa single ovigerous female
specimen from the GreatAustralian Bight, southern Australia, at a depthof
360 m. The new species somewhat resembles G. hakuhoae Takeda and
Hanamura from Indonesia and the Northwest Shelf and G. robusta Komai
fromthePhilippines,butischaracterizedbyaverystronglysinuousrostrum,
very strong and elongate branchiostegal spine on the carapace, unusually
thick and highly elevated median carinae on the abdomen and heavily
crenulateventrolateralmarginsofthetelson. Glyphocrangoneleplwsisthefirst
species of Glyphocrangonidae to be recorded from southern Australian
waters. The discovery of the new species brings the number of Australian
speciesofGlyphocrangonto11.
INTRODUCTION SYSTEMATICS
Shrimps of the genus Glyphocrangon A. Milne-
FamilyGLYPHOCRANGONIDAE
Edwards, 1881 exclusively inhabit depths greater
than 200 m. They are characterized by the Genus GlyphocrangonA.MilneEdwards,1881
unusually hard body integument strongly
sculptured by longitudinal carinae and/or Glyphocrangonelephassp.nov.
tubercles, teeth or spines, and the peculiar locking Figures1-3
mechanismoftheposterior abdominalsomites and
telson. Recently Komai (2004) reviewed species of Material Examined
the genus in the Indo-West Pacific region, Holotype; Southern Australia: Great Australian
recognizing 54 species, including 28 new species. Bight, 33°17'S, 128°32'E, 360 m, 19 March 1978,
He suggested that intensive collections would trawl, coll. M. Walker, ovigerous female CL 13.6
eventually reveal existence of more unknown mm(WAM-C 14783).
speciesfromtheIndo-WestPacific
.
Examination of material in the collection of the Description
Western Australian Museum, Perth, revealed a Body (Figure 1) robust. Integument of carapace
specimen of a distinctive undescribed species of andabdomennaked,glabrous.
Glyphocrangon. This new species, described herein Rostrum (Figures 2A, B) moderately narrow in
as G. elephas, is compared with G. hakuhoae Takeda posterior part, strongly deepened at about
&Hanamura, 1994, knownfromIndonesiaand the midlength, 0.7 times of carapace length, directed
Northwest Shelf and G. robusta Komai, 2004, from downwardinproximalpart,butstronglyupturned
thePhilippines.Thenewspeciesrepresentsthefirst in distal half; dorsolateral ridges strongly sinuous
species ofGlyphocrangonidae tobe recorded from inlateralview,with2pairsofshort,roundedteeth;
southernAustralia, as well as bringing thenumber proximal part of dorsolateral ridge between 2
ofspeciesofthegenusknownfromAustraliato11. lateral teeth rather low, devoid of longitudinal
Descriptive terminologygenerallyfollows Komai groove,anteriorpartdistaltoanteriorpairoflateral
(2004). Size of the specimen is indicated by teeth highly elevated; middorsal carina low,
postorbital carapace length (CL). The holotype of confined to distal 0.2 of rostrum; dorsal surface
the new species is deposited in the Western lackingtransverseseptaorrugosity;ventralsurface
AustralianMuseum(WAM). with shallow median groov'e becoming narrower
254 T.Komai
NewGlyphocrangort 255
posteriorly, flanked by bluntly edged ventrolateral in contact with anterior fourth carina. Marginal
carinae;midventralcarinaabsent. posterolateral comer not delineated. Lateral and
Carapace (Figures 1, 2A,C) 1.1 times longer than cervical grooves shallow. Lateromarginal groove
greatest width at about midlength; carinae and shallow.
tubercles eroded with minute pits. Anterior first First abdominal somite (Figure 1) with dorsal
(submedian) carinacomposedof3 greatlyunequal, elevation low, but clearly defined by shallow
low, blunt tubercles (first and second tubercles transverse groove, with 1 blunt tubercle on either
distinctly separated fromeach other, third tubercle side of median carina; median carina low, very
longest);posteriorfirstcarinathick,faintlybi-lobed; broad,notreachingposterodorsalmarginofsomite,
posteriorlobeconvergingtomidlineposteriorly,its terminating anterodorsally in broadly rounded
posterior end not overhanging posterodorsal projection. Dorsolateral carina low, thick, with
marginofcarapace. Anteriorsecond (intermediate) rounded anterior margin. Posterior section of
carina composed of 3 low, blunt tubercles; second, tergum with 5 or 6 low tubercles on either side of
smallest tubercle aligned with other tubercles; midline. Lateral carina low, broad, entire. Pleuron
posterior second carina composed of 3 low lobes with 1 blrmt submarginal tubercle anterolaterally;
(second lobe longest). Anterior third (antennal) posterior depression not abruptly delimited;
carinaveryshort,blunt,confinedtoantennalspine; anteroventralcomerweaklyproduced,blunt.
posterior third carina low, broad, faintly 3-lobed Second to fourth abdominal somites (Figure 1)
(anteriormostlobeshortest),terminatingobtuselyat with only few intercarinal tubercles; surfaces of
anterior end. Anterior fourth (lateral) carina carinae and tubercles minutely punctate; median
divided in 2 discontinuous lobes, slightly carinaeunusuallythick,posteriorendseachweakly
unaligned; anterior lobe weakly compressed tosomewhatproducedposteriorly;crosssectionsof
vertically, terminating anteriorly in blunt point; median carinae T-shaped; posterior transverse
posterior lobe low, weakly compressed vertically, groovesveryshallow;dorsolateralcarinaeshowing
slightly divergent posteroventrad against dorsal as low, rounded tubercles; pleura each with some
plane of carapace, terminating anteriorly in blrmt large, low tubercles orprotuberances;ventrallobes
point;posteriorfourthcarinalow,broad,parallelto of pleural elevations lacking prominent tubercle or
posterior third carina. Anterior fifth (sublateral) spine; pleural teeth greatly unequal, blunt, only
carina low, but clearly delineated; posterior fifth slightlycurvedlaterally.
carina very low, irregularly shaped, partially fused Fifth abdominal somite (Figure 1) humpy with
with posterior part of divided sixth (submarginal) rounded tubercles; anteriormediancarinashowing
carina. Sixth (submarginal) carina divided in two as blunt tubercle; posterior median carina short,
parts; anterior part low, roughly eroded; posterior thick, its posterior end rounded. Tergum with
part very low, irregularly shaped. Submarginal shallow dorsal groove; anterior submedian carina
posteroventral ridge very low, distinct from sixth showing as blrmt tubercle; posterior submedian
carina. Postorbital region unarmed, but with low, carinaehigh,thick,reachingnearlytoposterodorsal
blunt submarginal ridge extending to antennal margin of somite, slightly diverging posteriorly in
spine. Medianpartofgastric regionwith 2rows of dorsalview;pleuronwith2shortventralteeth.
3 or 4 tubercles on anterior part; posteromedian Sixth abdominal somite (Figure 1) with high,
region smooth. Lateral part of gastric region with somewhat compressed median carina, entire,
space between first and second carinae nearly flat, terminating posteriorly in large, blunt projection;
with 1 low tubercle; space between second carina dorsal margin smooth, convex in lateral view.
and lateral groove narrow, also with 1 small, low Tergum with 1 large, rounded tubercle on either
tubercle. Posterior dorsolateral region slightly side ofmediancarina;lateral carinacomposed of2
concave, smooth. Hepatic region with upper part large tubercles; posterolateral carina distinct,
only shghtly convex, with row of 2 low tubercles, slightly produced beyond posterolateral margin of
possiblyrepresenting trace ofanterior third carina; somite.Pleuronwith5largetubercles;lateroventral
lower part nearly flat, unarmed. Each part of carina extending onto posterolateral tooth;
branchial region unarmed. Subbranchial region posterolateral tooth strong, rather subacute,
with spacebetween anteriorfifth and sixth carinae noticeablyflaredlaterally.
moderately broad, shallowly depressed below, Telson (Figures 1, 2E) 0.8 times as long as
smooth, in contact with lower part of branchial carapace; anterior projection moderately high,
region. Antermal spines short, nearly straight in somewhat compressed laterally, directed
dorsal view, weakly ascending in lateral view posteriorly; dorsolateral carina smooth;
(angle about 15° against horizontal plane of ventrolateral carina strongly crenulate almost over
carapace).Branchiostegalspinesverystrong,visible entire length with short vertical tubercles or
indorsalview,directedforwardinbothlateraland roundedtubercles.
dorsalviews,extendingtodistalmarginofantennal Eye (Figures 1, 2A) relatively small for genus,
scale; lateral face with 2 inconspicuous ridges, not maximal diameter 0.15 ofcarapace length, without
256 T.Komai
Figure2 Glyphocrangon elephas sp. nov. A, anteriorpartofcarapace and cephalic appendages, lateralview (antennal
flagellumomitted);B,rostrum,ventralview;C,ventralpartofcarapace,ventrolateralview; D,leftantennal
scale, dorsal view; E, telson, dorsal view. Holotype ovigerous female (GL 13.6 mm; WAM-C 14783).
Abbreviations: A4, anterior fourth carina; A5, anterior fifth carina; AP6, anterior part of sixth carina; P4^
posterior fourth carina; P5, posterior fifth carina; PP6, posterior part of sixth carina; SPLR, submarginal
posterolateralridge;7,seventhcarina.
darkpigmentationinpreservative;ocularpeduncle marginofscaphocerite; marginal spines on distal2
withsmallanteromesialprocess. segmentsslender.
Antennular peduncle (Figure 1, 2A) reaching First pereopod (Figure 3A) with palm devoid of
distalmarginofscaphocerite; penultimate segment pubescence or short setae on lateral face; ischium
twice as long as wide. Outer flagellum with with moderately broad, distally acute ventral
moderatelylongaesthetasc-bearingportion. lamina. Second pereopods (Figure 3B) slightly
Antennalscaphocerite(Figures1,2A,D)elongate unequal with right chela smaller; neither reaching
oval, 0.33 times as long as carapace, 2.20 times distalmarginofscaphocerite;leftcarpuscomposed
longer than wide; dorsal surface naked; lateral of 22 articles. Posterior 3 pairs of pereopods
margin weakly convex, with distinct lateral tooth moderately stout. Third pereopod (Figure 3B)
arising at proximal 0.44 of scaphocerite length. overreaching distal margin of scaphocerite by
Carpocerite not reaching distal margin of length of dactylus; propodus without distal tuft of
scaphocerite. setae. Fourth pereopod (Figure 3D) reaching distal
Mouthparts not dissected, but typical of genus. margin ofscaphoceriteby tip ofdactylus; dactylus
Third maxilliped slightly overreaching distal (Figure 3E 0.78 times as long as propodus.
)
NewGlyphocrangon 257
Figure3 Glyphocrangon elephas sp. nov. Left pereopods. A, first pereopod, lateral view; B, second pereopod, lateral
view; C, third pereopod, lateral view; D, fourth pereopod, lateral view; E, dactylus of fourth pereopod,
dorsalview;Ffifthpereopod,lateralview.Holotypeovigerousfemale(CL13.6mm;WAM-C14783).
subspatulate, terminating in simple, acuminate Philippines, and together differ from all other
unguis partially obscured by tufts of setae arising congeners by the combination of the strongly
from just lateral to base of unguis; dorsal surface sinuously curved dorsolateral margins of the
shallowly broadly sulcate medially, without rostrum in female and the two unaligned lobes
distolateral groove; ventral surface not carinate in composingtheanteriorfourth(lateral)carinaonthe
midline. Fifth pereopod (Figure 3F) overreaching carapace. However, the new species is quite
midlength of scaphocerite by tip of dactylus; distinctive in having unusually thick and highly
dactylus 0.73 times as long as propodus, generally elevated median carinae on the second to fourth
similartothatoffourthpereopodinstructure. abdominal somites and the very strongly sinuous
Egg size 1.53-1.76 x 1.24-1.47 mm; number not rostrum. Other characteristics of the new species
recorded. include: the branchiostegal spine is very strong,
reaching the distal margin of the scaphocerite; and
Distribution the ventrolateral carina of the telson is strongly
Known only from the Great Australian Bight, crenulate with short vertical ridges or rounded
southernAustralia,atadepthof360m. tubercles.
Komai(2004)recordedthefollowing10speciesof
Remarks Glyphocrangon from Australian waters (Table 1); G.
Glyphocrangon elephas sp. nov. somewhat confusa Komai, 2004 (previously known from
resembles G. haknhoae from Indonesia and the Australia as G. investigatoris Wood-Mason, in
AustralianNorthwestShelfand G. robiista from the Wood-Mason and Alcock, 1891; see Jones &
258 T.Komai
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ACKNOWLEDGEMENTS Manuscript received 25 May 2004; accepted 22 September
2004
I am grateful to Diana Jones of the Western
Australian Museum for providing material. I also
thank Drs. Peter J. F. Davie and Shane T. Ahyong
for reviewing the manuscript and offering helpful
commentsforimprovements.