Gonodactylellus barberi, Ahyong & Erdmann, 2007

Ahyong, Shane T. & Erdmann, Mark V., 2007, Two New Species Of Gonodactylellus From The Western Pacific (Gonodactylidae: Stomatopoda), Raffles Bulletin of Zoology 55 (1), pp. 89-95 : 92-94

Gonodactylellus barberi new species

( Figs. 2 , 3 )

Gonodactylellus hendersoni – Barber & Erdmann, 2000: 22 [not G. hendersoni ( Manning, 1967) = G. demanii ( Henderson, 1893) ].

Material examined. – Holotype: USNM 304372 a, male (TL 24 mm), Spermonde Archipelago , Sulawesi, Indonesia, 5 ° 10'S 119 ° 50'E, dead coral rubble, 0–2 m, coll. M. Erdmann, 1996.

Paratypes: USNM 304372 b, 2 males (19–20 mm), 8 females (13– 27 mm), 2 juvenile females (11–12 mm), type locality .

Diagnosis. – Mandibular palp 3-segmented. Telson with spiniform submedian denticles; lateral teeth indicated by a shallow, narrow notch, apex blunt, not projecting well off margin of telson. Telson mid-dorsal carinae posteriorly armed, otherwise smooth; mid-dorsal carinae armed posteriorly; submedian tooth armed dorsally with 1 or 2 spines in longitudinal row; intermediate tooth with 0–2 dorsal spines. Telson ventral surface with carina on submedian and intermediate teeth. Uropodal exopod proximal segment inner margin smooth, non-setose, with distal ventral spine; exopod distal segment inner margin smooth, non-setose. Uropodal endopod narrow, length 2.60–2.85 breadth; inner margin smooth, non-setose.

Description. – Eyes elongate; cornea subconical. Ocular scales low, separate, bases transverse. A1 peduncle length 0.52–0.64 CL. A2 scale length 0.38–0.43 CL.

Rostral plate as long as broad; basal portion with transverse or slightly concave anterior margins; anterolateral margins angular; lateral margins divergent anteriorly; median spine longer than base, laterally flattened, with obtusely angular ventral keel.

Raptorial claw dactylus with shallow notch; propodus with proximal movable spine, opposable margin sparsely pectinate proximally.

Mandibular palp 3-segmented.

TS6–7 lateral processes subequal to or slightly broader than that of TS6; lower margins subtruncate. TS8 anterolateral margin rounded; sternal keel obsolete.

PLP1 endopod with lateral lobe on posterior endite.

AS 1–5 posterolateral angles unarmed. AWCLI 700–851. AS 6 with submedian and intermediate bosses armed in females and juvenile males, apices blunt or obsolete in adult males; lateral bosses armed at all sizes.

Telson broader than long; with 9–12 spiniform submedian denticles; intermediate teeth distinct, longer and sharper in females, apices extending posteriorly well beyond apices of intermediate denticles; lateral teeth indicated by a shallow, narrow notch, apex blunt, not projecting well off margin of telson. Telson median carina tumid in males, so inflated as to obscure accessory median carinae, together with a group of up to 3–8 posterior spines (1 or 2 spines on median, 1–3 spines on each accessory median); anterior submedian carina usually with 0–3 (usually 2) spines in longitudinal row; submedian tooth armed dorsally with 1 or 2 spines in longitudinal row (1 female with spinule mesial to anterior spine); intermediate tooth with 0–2 dorsal spines; knob absent; submedian and intermediate teeth with ventral carina.

Uropodal protopod terminal spines with length subequal; upper proximal surface with obtuse swelling behind dorsal carina. Uropodal exopod proximal segment outer margin with 9 or 10 (usually 10) movable spines, distalmost reaching or slightly exceeding apex of distal segment; inner margin smooth, non-setose; distal margin with ventral spine; exopod distal segment with outer margin setose, inner margin smooth, non-setose. Uropodal endopod narrow, length 2.60–2.85 breadth; distal half of outer margin setose, remainder smooth, non-setose.

Colour in life. – Overall light green to light brown; with two thin, white transverse bands, one across carapace (arising twothirds posteriorly) and continuing across merus, and a second across posterior third of AS 6 and anterior quarter of telson, continuing across uropods. General subtle brown mottling over body, with three iridescent blue spots medially on carapace behind white transverse band. Large blue iridescent spot medially on TS6–7 and AS 1, with 5 smaller blue iridescent spots spaced evenly across dorsal surface all exposed thoracic and abdominal somites. Meral spot fleshtoned with small black spot distally.

Measurements. – Male (n = 3) TL 19–24 mm, female (n = 9) TL 13–29 mm. Other measurements of holotype: CL 5.85 mm, A1 peduncle length 3.25 mm, A2 scale length 2.25 mm, AS 5 width 4.10 mm.

Etymology. – Named barberi , after our colleague Paul Barber, for his studies into the genetics and population structure of gonodactyloid stomatopods.

Habitat. – Prefers areas of sand and dense coral rubble on calm, shallow (0–2 m depth) coastal reef flats. Found only on reefs close to mainland rivers (never more than 10 km from river outlets, and generally much closer); seemingly very tolerant of high sediment loads and lowered salinities.

Remarks. – Gonodactylellus barberi closely resembles G. molyneux Ahyong, 2001 (from Australia) and G. snidvongsi ( Naiyanetr, 1987) (presently believed to range from Thailand to Japan and Hawaii) in completely lacking setae on the inner margin of the uropodal endopod, the width of which is less than one-third of the telson width. The new species is readily distinguished from G. snidvongsi in having a 3- instead of 2- segmented mandibular palp, in the distinctness of the lateral primary teeth of the telson, in which the apices are blunt instead of sharp, not markedly standing out beyond the outline of the telson. Additionally, adult G. barberi differ from G. snidvongsi in having fewer dorsal spines on the telson carinae. The dorsal carina of the submedian teeth in G. barberi bears a conical spine at the base of the submedian tooth, but a second may be present near the midlength in specimens of about 20 mm or larger. Occasionally, in specimens 24 mm TL or larger, an additional spine may be present mesial to the basal spine. In contrast, the spination of the carina of the submedian teeth develops at a much smaller size in G. snidvongsi . By 16 mm TL in G. snidvongsi , a cluster of two or more (usually three or more) spines is always present at the base of the submedian teeth. In the segmentation of the mandibular palp, form of the lateral primary telson teeth, and telson spination, G. barberi resembles G. molyneux . Gonodactylellus barberi differs from G. molyneux , however, in bearing a narrower uropodal endopod in which the width is about one-third instead of one-half the length, and in which the submedian denticles are spiniform and distinct, rather than fused into the margin.

As in G. snidvongsi and G. molyneux , telson spination in G. barberi generally increases with size. Thus, specimens of G. barberi up to 20 mm TL usually have a single dorsal spine on the submedian and intermediate carinae of the telson and 1 or 2 posterior spines on the accessory median and anterior submedian carinae. The telson of specimens exceeding 20 mm TL may have 2 dorsal spines on the submedian carinae, 1 or 2 spines on the intermediate carinae, and 2 or 3 posterior spines on the accessory median and anterior submedian carinae. Additionally, sexual dimorphism is evident in the strongly inflated telson carinae of adult males in which the accessory median carinae are subsumed by the anterior submedian carinae, and the associated spines are blunt. The intermediate primary teeth of the telson are also longer and sharper in females than adult males.

In view of the similarity between G. barberi and G. snidvongsi , some published records of the latter (under the names G. hendersoni or G. demanii ) could well be based on the former. Holthuis’ (1941) records of G. demanii from Indonesia, judging from his figure 8, appear to be based on G. snidvongsi . Similarly, two forms of G. hendersoni reported by Barber & Erdmann (2000) from Java and southern Sulawesi, Indonesia (as G. hendersoni J and G. hendersoni S), are referable to G. snidvongsi and G. barberi , respectively.

Distribution. – Presently known only from Spermonde Archipelago, Sulawesi, Indonesia, from reef areas under significant terrigenous influence.

Figures

Fig. 2. Gonodactylellus barberi new species, holotype male (TL 24 mm), USNM 304372a, Spermonde Archipelago, Sulawesi, Indonesia: A, anterior; B, right eye, lateral view; C, ocular scales; D, rostral plate, right lateral view; E, right A2 protopod; F, right raptorial claw, lateral view; G, TS6–8, right lateral view; H, AS5–6, telson and Uropod; I, AS3–5, right lateral view; J, right uropod, ventral view; K, telson, right lateral view; L, telson, ventral view; M, right PLP1 endopod, anterior view. Scale bar: A–L = 1.0 mm, M = 0.5 mm.

Fig. 3. Gonodactylellus barberi new species, paratype female (TL 26 mm), USNM 304372b, Spermonde Archipelago, Sulawesi, Indonesia: A, rostral plate and ocular scales; B, AS5–6, telson and Uropod; C, right uropod, ventral view; D, telson, right lateral view; E, telson, ventral view. Scale bar: A = 0.7 mm, B–E = 1.0 mm.