DIOGENES OF SINGAPORE AND THE MALAY PENINSULA 



37 



REMARKS. The first maxilliped of Diogenes species is not often 

 described or illustrated, but in those few species for which it has 

 been (e.g.,Tirmizi and Siddiqui, 1982a), a two-segmented exopodal 

 flagellum is typical. Diogenes inglei sp. nov. is the only species of 

 the genus currently known to lack the flagellum; in its place are a 

 pair of short setae (Fig. 1 c). Whether this loss is unique to D. inglei 

 sp. nov. or simply reflects inadequate examinations of other species 

 remains to be determined. It should be noted, however, that the only 

 hermit crabs routinely lacking a flagellate first maxilliped are 

 parapagurids or coenobitids. Diogenes inglei sp. nov. also appears 

 distinctive in having the sixth abdominal segment armed with spines 

 on the posterolateral and posterior margins. This again may simply 

 reflect inadequate observations of other species. 



Diogenes rectimanus Miers, 1884 

 (Fig. 10b) 



Diogenes rectimanus Miers, 1884:262, pi. 27, fig. c; Gordan, 

 1956:318 (in part; lit.). 



? Diogenes rectimanus: Henderson, 1893:419; Alcock, 1905b:71, 

 pi. 6, figs 8, 8a, pi. 7, fig. 2, 2a; Ajmal Khan and Natarajan, 

 1984:20, fig. 17; Morgan, 1987b:175; Haig and Ball, 1988:167; 

 Rahayu and Forest, 1995:395. 



Non Diogenes rectimanus: Lanchester, 1902:366. 



Material examined. Holotypecf(SL = 4.30 mm), Prince of 

 Wales Channel, Torres Strait; BMNH 1882.7. 



Redescription. Shield slightly longer than broad, almost 

 subquadrate; anterior margin between rostrum and lateral projec- 

 tions slightly concave, with 5 or 6 small tuberculate spinules near 

 bases of lateral projections; anterolateral margins sloping; posterior 

 margin truncate; dorsal surface with few transverse spinulose ridges 

 laterally. Rostrum broadly rounded; lateral projections each with 

 rather strong marginal spine, branchiostegial margins each with 5 or 

 6 moderately well developed spines. 



Ocular peduncles approximately 0.80 length of shield, moder- 

 ately stout; cornea not dilated; ocular acicles with straight inner 

 margins, broadly rounded anterolaterally, with 3 small, but promi- 

 nent spines and several additional smaller spinules, not extending 

 entire length of terminal margin. Intercalary rostriform process 

 reaching approximately to distal third of ocular acicles, broad 

 basally, tapering to moderately slender subacute tip. 



Antennular peduncles overreaching corneae by almost entire 

 length of ultimate segment. Ultimate segment with few setae dorsally 

 and tuft distally on both ultimate and penultimate segments; basal 

 segment unarmed. 



Antennal peduncles overreaching distal margin of cornea by 

 0.20-0.35 length of ultimate segment. Fifth segment with row of 

 tufts of setae on ventral margin; fourth segment with few scattered 

 setae and small spine on dorsolateral distal margin; third segment 

 with tuft of setae; second segment with small spine at dorsolateral 

 distal angle and very small spine on dorsomesial distal angle, 

 ventrolateral distal angle with small spinule; first segment with row 

 of small spinules on distal margin laterally and similar row of small 

 spinules on lateral margin ventrally. Antennal acicle not reaching to 

 apex of fourth segment, with strong bifid spine and 4 accessory 

 strong spines on mesial margin, few tufts of setae on lateral margin. 



Maxillule without external endopodal lobe. 



Dactyl of left cheliped (Fig. 3b) approximately 0.35 longer than 

 palm; double row of spines on upper margin, outermost strongest, 

 row of equally strong spines adjacent to upper margin, outer surface 

 with scattered small spinose tubercles and very short setae; cutting 

 edge with multiple series of small calcareous teeth, largest in distal 



third; inner surface with row of low protuberances. Palm slightly 

 shorter than carpus; upper surface with irregular triple row of spines, 

 outer surface with slightly concave area just below upper margin 

 with few scattered spinules and tubercles and tufts of short setae, 

 upper outer face with adjacent longitudinal row of moderately strong 

 spines in proximal half, not reaching articulation of palm, remaining 

 outer surface with rather widely-spaced small spines; proximal 

 margin with row of stronger spines continuing to lower margin, 

 lower outer surface of palm spinose, to with short setae; inner surface 

 with few very small tubercles in lower half; lower margin with row of 

 strong, outwardly directed spines, decreasing in size on fixed finger, 

 and adjacent second row of much smaller spines; surface of fixed 

 finger with spinulose tubercles. Carpus with row of moderately blunt 

 spines on upper margin (distal 2 or 3 stronger), outer surface convex, 

 with series of small tuberculate spines, lower margin with strong 

 spine at lower distal angle, inner and lower surfaces with few 

 tubercles. Merus triangular; dorsal surface rounded, with transverse 

 rows of small spines or spinules continuing onto lateral surface 

 dorsally, one such row adjacent to laterodistal margin appreciably 

 longer, mesiodistal margin with row of tuberculate spines, mesial 

 face tuberculate in ventral half, ventromesial margin with row of 

 broad, low bifid spines, ventrolateral margin with row of spines 

 distally becoming spinulose tubercles proximally, ventral surface 

 with numerous low bifid spinules. Ischium with row of small tuber- 

 cles on laterodistal margin ventrally and proximal margin. 



Right cheliped with dactyl approximately 0.35 longer than palm; 

 upper surface with double row of small spines, outer surface with 

 row of slightly larger spines, both surfaces generally concealed by 

 long setae; cutting edge with row of calcareous teeth, terminating in 

 calcareous claw, slightly overlapped by fixed finger. Palm approxi- 

 mately 0.65 length of carpus: upper surface somewhat spinulose, 

 small spines or spinules forming quasi transverse rows; outer face 

 with few small spines or low protuberances and tufts of setae; fixed 

 finger with 2 rows of moderately strong spines on outer surface, 

 cutting edge with quite prominent calcareous teeth: inner surface of 

 palm with tufts of setae, row of widely-spaced tubercles on fixed 

 finger. Carpus with row of spines on upper margin and second 

 adjacent row on upper outer face, outer distal margin with 2 spines, 

 low protuberances on lower outer face, surfaces all with long setae. 

 Merus with short transverse spinulose ridges and tufts of setae on 

 dorsal margin, lateral face with low spinulose protuberances; vent- 

 rolateral margin with 2 acute spines distally, low sometimes bifid 

 spinulose protuberances proximally extending onto ventral surface; 

 mesial face generally glabrous, ventromesial margin with row of 

 small spinules distally. double row of stronger spinules proximally. 

 Ischium with 2 spinules on ventromesial margin. 



Ambulatory legs similar. Dactyls 0.25-0.35 longer than propodi; 

 dorsal margins of dactyls each with almost double row of long stiff 

 dense setae, lateral faces with faint transverse sulcus in proximal 

 half and row of long setae, ventral margins each with row of long 

 setae proceeding onto lateroventral margin distally, mesial faces 

 also with row of long stiff dense setae ventrally and second row of 

 stiff setae beginning in upper half and progressing ventrally toward 

 claw. Propodi approximately 0.25 longer than carpi, right with 

 dorsal, ventral, mesial and lateral tufts of setae, left with tufts of 

 setae accompanied by row of spinules dorsal surfaces, strongest on 

 third. Carpi each with row of acute spines, somewhat shorter on 

 third. Meri with dorsal and ventral tufts of setae; second with 

 spinulose protuberances ventrally on lateral faces and row of small 

 spinules on ventral margin, ventrolateral distal margin also with row 

 of spinules. Ischia with 2 or 3 spinules (second) or unarmed (third). 

 Sternite of third pereopods with indistinctly bilobed anterior lobe, 

 each pseudo-lobe with tuft of setae. 



