Stratiotes micheleae, Rahayu, Dwi Listyo, 2005

Rahayu, Dwi Listyo, 2005, Additions to the Indonesian fauna of the hermit crab genus Pseudopaguristes McLaughlin and a further division of the genus Paguristes Dana (Crustacea: Decapoda: Paguroidea: Diogenidae), Zootaxa 831, pp. 1-42 : 16-20

Stratiotes micheleae n. sp. ( Figs. 6 , 7 )

Material examined. Holotype: male, 4.6 mm, without right third pereopod, northeast of Binongko Island, Snellius II, stn 37, 05°54.2'S, 123°57.0'E, 350–500 m, 10 Sep 1984 ( MZB). Paratypes: 2 females, 3.0, 4.0 mm, 1 ovig. female, 3.5 mm, southeast of Karang Kaledupa, Snellius II, stn 24, 5°57'S, 123°49'E, 350–500 m, 0 9 Sep 1984 ( MZB); 1 male, 3. 5 mm, CORINDON, stn 229, 00°02.2'N, 119°49.8'E, 4 Nov 1980, 445– 411 m ( MNHN); 1 male, 6.5 mm, Galathea , stn. 500, 07°34'S, 132°44'E, 390 m, 25 Sep 1951.

Description. Biserial phyllobranchiae. Shield ( Fig. 6 a) 1.2 longer than broad; lateral margins sloping, short transverse row of small spines and tuft of setae on dorsal surface. Rostrum triangularly obtuse, reaching distal 0.3 of ocular acicles, about same length as lateral projections, terminating in acute spine. Lateral projections triangular, with acute marginal spine. Ocular peduncles stout, 0.5 length of shield; slightly inflated basally and in corneal region; corneal diameter 0.3 of peduncular length; ocular acicles small, distinctly separated basally, terminating in simple spine. Antennular peduncles, when fully extended, overreaching corneas by entire length of distal segment; basal segment with distal acute spine dorsomesially and dorsolaterally and median spine dorsolaterally. Antennal peduncles approximately same length or slightly longer than ocular peduncles; fifth segment unarmed; fourth segment with small distolateral spine; third segment with ventromesial distal angle strongly produced, terminating in strong spine; second segment with dorsolateral distal angle produced, terminating in prominent bifid spine, subdistal spine on lateral margin, strong spine on distal margin; first segment unarmed. Antennal acicles reaching distal margin of ultimate peduncular segment, terminating in prominent bifid spine, mesial margin with 3–4 strong spines, lateral margin with 2–3 strong distal spines. Antennal flagellum same length or slightly longer than shield, consisting of about 20 articles, proximal articles with short, sparse setae, distal articles with longer and denser setae. Basis of third maxilliped with 1 distoventral spine; merus with 3–4 small spines on ventral margin.

Chelipeds ( Figs. 7 a–c) subequal, armature similar. Ventromesial margins of ischia each with row of small spines. Meri each with denticles on dorsal margin; ventromesial margins each with row of strong spines, less prominent spines on ventrolateral margins and sparse setae, mesial faces glabrous; lateral faces with scattered small tubercles near dorsal and ventral margins. Carpi 0.6 length of meri, row of 3–4 corneous­tipped spines on each dorsomesial margin; dorsal surface with longitudinal rows of moderately small spines near dorsomesial and dorsolateral margins; long and sparse setae on dorsal surface. Palms 0.6 length of carpi, dorsomesial margins each with 3 strong, corneous­tipped spines; dorsal surfaces each with several irregular rows of small, occasionally corneous­tipped spines, becoming closely­spaced on fixed finger; ventral surfaces each with single row of tubercles medially, extending onto fixed finger, tuft of setae at base of each tubercle; cutting edge with small calcareous teeth in proximal 0.7, corneous teeth in distal 0.3 terminating in corneous claw; dorsal surface with sparse long setae. Dactyls approximately twice as long as palms; cutting edge with small calcareous teeth in proximal halves, corneous teeth in distal halves, terminating in small corneous claws. Dorsomesial margins each with row of small, occasionally corneous­tipped spines; dorsal surface with scattered small spines and tufts of setae; mesial surfaces densely covered with small corneous spines, sparsely setose; no hiatus between dactyl and fixed finger.

Second pereopods ( Fig. 7 f) slightly shorter than third, left and right second pereopods with similar armature. Dorsal margins of meri unarmed, ventromesial margins each with row of minute spines. Carpi approximately 0.7 length of meri, each with dorsal row of 6 irregular, occasionally corneous­tipped spines; lateral faces convex, each with longitudinal sulcus near dorsal margin. Propodi slightly longer than carpi, each with dorsal row of 9 large corneous­tipped spines; mesial surfaces each with row of setae near dorsal margins. Dactyls 1.5 length of propodi, weakly curved, dorsal margins each with row of small corneous­tipped spines, becoming smaller and spiniform distally, obscured by tufts of setae; mesial surfaces with scattered setae; ventral margins each with row of small spiniform setae.

Meri of third pereopods ( Figs.7 d, e) with long setae on dorsal and ventral margins. Carpi 0.8 length of meri, each with small subdistal spine on dorsal margin; lateral surfaces convex, each with longitudinal sulcus near dorsal margin; long setae on dorsal and ventral margins. Propodi unarmed, long setae on dorsal and ventral margins, mesial faces with long, rather dense setae. Dactyls almost 1.6 length of propodi; each dorsal margin with long setae; row of spiniform setae and long simple setae on dorsomesial margin and mesial face; ventral margin with spiniform setae and long simple setae. Fourth pereopod with preungual process ( Fig. 6 b).

Male first pleopods ( Fig. 6 d, e) slender; inferior lamella rounded, distal margin with row of hook­like spines. External lobe elongate, tip slightly curved, separated from internal lobe by narrow cleft; internal lobe broad. Female brood pouch small, triangular, with sparse, short setae.

Telson ( Fig. 6 c) with asymmetrical posterior lobes, left lobe larger than right; cleft separating two lobes narrow and deep. Terminal margins of left and right lobes each with 6 corneous­tipped spinules, closely­spaced near cleft.

Etymology. This species is dedicated to the late Michèle de Saint Laurent. Her help at the beginning of this work is greatly appreciated.

Habitat. The species was collected from substrate with calcareous stones, dead corals and sponges.

Distribution. Southeast of Sulawesi and Macassar Strait, Indonesia

Remarks. The form of male first pleopod varies in relation to the size of the individual: the distal margin of inferior lamella in the small male paratype (SL 3.5 mm) was without a row of hook­like spines, while in holotype and other paratype the row of hook­like spines was well developed.

Stratiotes micheleae n. sp. resembles S. ngochoae n. sp., subsequently described in this paper, in having stout ocular peduncles and dense spinules on the mesial surfaces of dactyls of the chelipeds. However, the more significant differences, include simple instead of bifid ocular acicles; ventral margins of the meri of the second and third pereopods that are smooth or armed only with tiny spinules ventromesially rather than bearing stronger spines. Additionally, the terminal margin of the telson of S. micheleae is armed with six small spines while in S. ngochoae it is armed with four to 10 large spines. The form of male first pleopod of specimen of the same small size of both species is notably different. In S micheleae the distal margin of inferior lamella is without a row of hook­like spines, while in S. ngochoae the hook­like spines formed several rows on the distal margin and dorsal surface of inferior lamella.

Figures

FIGURE 6. Stratiotes micheleae n. sp., holotype, male, 4.6 mm (MZB): a, shield and cephalic appendages, setae omitted; b, left fourth pereopod, setae omitted; c. telson; d, e, right first pleopod, setae omitted; d, external view; e, internal view. Scales equal 1 mm.

FIGURE 7. Stratiotes micheleae n. sp., holotype, male, 4.6 mm (MZB): a – c, left cheliped, setae omitted; d, e, left third pereopod, setae partially omitted; f, left second pereopod; a, dorsal view; b, dorsolateral view; c, e, mesial view; d, f, lateral view; Scales equal 1 mm.