Enosteoides spinosus, Hiller & Werding, 2022

Hiller, Alexandra & Werding, Bernd, 2022, Multigene phylogeny of the Indo-West Pacific genus Enosteoides (Crustacea, Decapoda, Porcellanidae) with description of a new species from Australia, Zoosystematics and Evolution 98 (2), pp. 387-397 : 387

Enosteoides spinosus sp. nov.

Figs 1 , 2a-e , 3

Material examined.

Holotype: WAM C54778 , ♂, 3.5 × 3.4 mm. INDIAN OCEAN, WESTERN AUSTRALIA, KIMBERLEY DISTRICT: Beagle Reef , 15°19.60'S, 123°32.15'E, Station 73/K11-T1, intertidal, 19 Oct 2011, A.M. Hosie leg.

Paratypes: INDIAN OCEAN, WESTERN AUSTRALIA, KIMBERLEY DISTRICT: White Island , 15°58.58'S, 124°20.40'E, Station 68/K11-T1, 14 m depth, 17 Oct 2011, A.M. Hosie leg., WAM C54777 , 1♂, 4.2 × 4.1 mm; White Island , 15°58.58'S, 124°20.40'E, Station 68/K11-T1, 14 m depth, 17 Oct 2011, A.M. Hosie leg., WAM C77600 , 1♀, 3.3 × 3.4 mm; Mavis Reef , 15°32.32'S, 123°36.50'E, Station 77/K11-T1, 12 m depth, 20 Oct 2011, A.M. Hosie leg., WAM C48628 , 1♂, 3.2 × 3.0 mm; Jamieson Reef , 14°32.32'S, 125°32.95'E, Station 111/K12-T2, 4 m depth, 20 Oct 2011, A.M. Hosie leg., WAM C54780,1 ♀, 2.2 × 2.2 mm; Patricia Island , 14°98.98'S, 125°22.43'E, Station 114/K12-T2, 13 m depth, 22 Oct 2011, A.M. Hosie leg., WAM C54781 , 1♂, 3.0 × 2.6 mm; Beagle Reef , 15°13.13'S, 123°32.20'E, 75/K11-T1, 13 m depth, 20 Oct 2011, A.M. Hosie leg., WAM C54779 , 1♂, 2.3 × 2.3 mm; Long Reef , 13°37.37'S, 125°44.56'E, Station 44/K10-T1, 12 m depth, 20 Oct 2010, A.M. Hosie leg., WAM C45725 , 1♀, 4.6 × 4.8 mm; Beagle Reef , 15°60.60'S, 123°32.15'E, Station 73/K11-T1, Intertidal , 19 Oct 2011, A.M. Hosie leg., SMF58470 (exWAM C54778 b), 1♀ (ov), 3.6 × 3.7 mm; WEST PACIFIC OCEAN, AUSTRALIA: Queensland, Heron Island, NE side of Wistari Reef, 23°93.93'S, 151°53.41'E, rubble from edge of spur, 3.5 m depth, 11 Apr 2003, R. Wetzer, N.L. Bruce, N.D. Pentcheff leg., LACM CR-21354 (RW03.121), 1♀, 4,0 × 3.9 mm, 1♀ (ov), 3.9 × 4.2 mm .

Diagnosis.

Carapace hexagonal, broadest at mesobranchial level; dorsal surface strongly areolate, with spines on hepatic and epibranchial regions; acute spines on orbital, epibranchial and mesobranchial borders; front prominent, trilobed in frontal view, median lobe pronounced, lateral lobes each with a sharp terminal spine. Cheliped carpus about three times as long as wide, dorsal surface heavily eroded, with two broad longitudinal ridges, anterior margin straight with a row of three or more slender spines, posterior margin with five or six strong teeth; manus broad, depressed dorsoventrally, dorsal surface with irregular granules and a prominent crest on mid-line, inner border with strong, upright tooth; outer border concave, with row of sparse strong spines, dactylus with rounded median crest on dorsal surface and strong spines on inner border. Telson broad, composed of five plates.

Description.

Carapace about as long as wide, broadest at mesobranchial level; dorsal surface strongly areolate, regions distinct and separated by deep grooves; protogastric crest blunt, but steep, with scattered, stiff setae. Front prominent, truncate in dorsal view, trilobed in frontal view, lateral lobes subparallel, each with a sharp, forwardly directed spine terminally, followed inwards by a smaller, rounded tooth; median lobe pronounced exceeding lateral lobes, outer borders with a row of small, acute spines, decreasing in size posteriorly; frontal margin with long, stiff setae.

Orbits relatively shallow, each with one prominent supraorbital spine and a smaller spine at outer orbital angle. Hepatic region with a strong, forwardly directed spine above elevation of median part; hepatic margin with a prominent spine. Epibranchial region with small spines on elevation. Mesobranchial border with three spines, anterior two spines strong, third spine smallest, located near metabranchial region.

Sidewalls broad, surface granulated and eroded, with transverse ridge, partly covered with long, feathered setae; anterior margin ventrally with a row of forwardly directed blunt spines.

Anterior margin of third thoracic sternite slightly convex, lateral lobes prominent, resembling forwardly directed horns. Anterior margin of fourth thoracic sternite concave.

Eyes moderately large, ocular peduncles largely visible from dorsal side, distally with a distal, forwardly directed stiff seta, dorsal extension into cornea rounded.

Basal segment of antennular peduncle elongate, inner and outer lobes of anterior margin each with a terminal strong spine, inner lobe with a row of smaller spines on inner border. First segment of antennal peduncle strongly produced forwardly, broadly in contact with orbital margin, anterior margin bent upwards with a bifurcated, upwardly directed lobe; second to fourth segments movable, second segment short, with small spine at posterior distal end; third segment elongated with strong anterodistal spine; fourth segment rounded with small anterodistal spine. Antennal flagellum about 2.5 times as long as carapace, articulations thickened distally, bearing some stiff setae.

Ischium of third maxilliped broad, rounded distally; merus triangular, slightly concave distally; inner margin with some small spinules on distal edge; carpus with a triangular, spine-tipped projection on inner margin; propodus broad at proximal end, narrower distally; dactylus elongate, rounded on distal margin.

Chelipeds subequal, slender, dorsal surface heavily eroded. Merus granulated with scattered, irregular, scale-like and acute protuberances on dorsal surface, anterodistal margin produced into a broad, rounded lobe with irregular protuberances and squarrose outer border. Carpus about three times as long as wide; dorsal surface with two broad longitudinal ridges, one running along mid-line, ending distally in a serrated lobe; another ridge along anterior border, separated from median ridge by a deep, steep grove; anterior margin straight, with row of three or more slender, distally somewhat curved spines of different size; posterior margin slightly convex, separated from dorsomedian ridge by a steep slope, bordered with five or six massive, distally curved teeth. Manus broad, depressed dorsoventrally, outer border concave; surface of propodus with large, irregular granules and a prominent, granulated longitudinal crest; outer border concave on median part, with a row of sparse, massive spines bearing long, simple setae. Dactylus with rounded median crest on dorsal surface and a row of massive spines on outer border.

Merus of walking legs smooth with scattered, simple and feathered setae; upper border with an acute spine near distal end, additional spines sometimes present. Carpus with longitudinal depression and some stiff setae on upper side, with a strong spine; additional spines sometimes present on median part. Propodus slender, dorsal margin with one to three spines on different positions. Dactylus with four movable spines ventrally.

Telson broad, composed of five plates.

Etymology.

The specific name Enosteoides spinosus refers to the extremely spiny appearance of the new species.

Distribution.

Enosteoides spinosus sp. nov. has been so far reported from the Australian coasts of the Kimberley and Queensland Districts.

Ecology.

The species was found in the intertidal region to a depth of 14 m, in patchy reef structures with invertebrates such as sponges, hydroids, hard and soft corals and in areas with coral rubble, coarse sediment and a fine dusting of silt.

Colouration.

The specimens from Kimberly had been recently preserved at the time of examination and colouration was greyish-brown.

Remarks.

The new species gives a first impression of being morphologically distant from the other species of Enosteoides as currently defined, mainly due to the excess of sharp spines ornamenting the carapace and chelipeds. The new species is morphologically closer to E. ornatus than to any other species in the genus. Common characters to the two species are the spiny basal article of the antennular peduncle, the distinct spines on supra-orbital, hepatic and branchial regions and the spiny or tuberculate surface of the outer half of the palm of the chelipeds. The two main diagnostic characters of the new species is the telson, which is composed of five plates, instead of seven, a condition present in all other congeneric species and the proximal margin of the carpus, which bears sharp teeth in the new species, while it bears small denticules in E. ornatus .

Figures

Figure 1. Enosteoides spinosus sp. nov., female paratype WAM C 45725, Indian Ocean, West Australia, Kimberly District. Left cheliped absent, symmetrically complemented in the figure. Scale bar: 2 mm.

Figure 2. Enosteoides spinosus sp. nov., female paratype WAM C 45725, Indian Ocean, West Australia, Kimberly District. a. Left lateral view; b. Front, anterior dorsal view; c. Third and fourth thoracic sternites, ventral view; d. Telson, ventral view; e. Basal segment of left antennular peduncle, ventral view; f. Third maxilliped, ventral view. Scale bar: 1.0 mm.

Figure 3. Enosteoides spinosus sp. nov., female paratype LACM CR- 21354, habitus, Pacific Ocean, East Australia, Queensland, Heron Island. a. Dorsal view; b. Ventral view. Scale bar: 4.0 mm.