Dardanus sanguinolentus
Creators: name: Malay, Maria Celia (Machel) D.
name: Rahayu, Dwi Listyo
name: Chan, Tin-Yam
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Diogenidae
Dardanus
Dardanus sanguinolentus

description: Dardanus sanguinolentus (Quoy & Gaimard, 1824)
(Figs. 4A, 5C)
Pagurus sanguinolentus Quoy & Gaimard, 1824: 532, Fig. 2, pl. 79 (? Mauritius, type locality, see Forest, 1953b, p. 560); Forest, 1953b: 559–560, Figs. 12–14 [in part]; Fize & Serène, 1955: 166–173, Fig. 25, pl. 4 nos. 4–5 [in part].
Pagurus euopsis – Yap-Chiongco, 1938: 200; Estampador, 1937: 503 (in part).
Dardanus lagapodes – Cassidy, 2005: 109–112, Figs. 10–12 (misspelling of Dardanus lagopodes) [not Dardanus lagopodes (Forskål 1775)].
Dardanus lagopodes – Lewinsohn, 1969: 32, Fig. 1–2, pl. 2 [in part]; Ball & Haig, 1972: 92–93 [in part]; McLaughlin et al., 2007: 91–93, 3 unlabellled figures [in part, particularly p. 93, Fig. c] [not Dardanus lagopodes (Forskål, 1775)].
Pagurus depressus Heller, 1961: 22 (Red Sea, type locality); McLaughlin & Dworschak, 2001: 150–151.
? Dardanus Hellerii Paul’son, 1875: 90, 91, pl. 12, Fig. 4, 4 a–c (Red Sea, type locality).
Material examined. Holotype: female SL 26 mm (MNHN Pg. 1304),? Mauritius; 1 ovig. female SL 4.3 mm (ZRC), stn B3, Arco Point, Panglao I., 9°33.5′N, 123°48.6′E, 8 m, 31.v.2004; 1 male SL 6.7 mm (ZRC), stn M2, west end of Alona Beach, Panglao I., 9°32.8′N, 123°45.9′E, 0–2 m, 30.v.2004; 1 male SL 7.0 mm (ZRC), stn M18, Gak-Ang Islet, off Panglao I., 9°33.0′N, 123°45.5′E, 0–1 m, 10 & 12.vi.2004; 1 ovig. female SL 6.3 mm, 1 female SL 6.9 mm (ZRC), stn R6, Baclayon, Bohol I., Loay, Bohol I., 9°36.6′N, 123°57.8′E, 5–12 m, 31.v.2004; 1 female SL 6.9 mm (ZRC), stn R6, Baclayon, Bohol I., Loay, Bohol I., 9°36.6′N, 123°57.8′E, 5–12 m, 31.v.2004; 2 females SL 5.2–7.1 mm (ZRC), stn R10, Biking, Panglao I., 9°35.3′N, 123°50.5′E, 2–10 m, 1.vi.2004; 1 female SL 8.0 mm (ZRC), stn R16, Black Forest, Panglao I., 9°31.1′N, 123°41.3′E, 6–22 m, 4.vi.2004; 2 males SL 5.2–6.4 mm (ZRC), stn R21, Rico’s Wall, Panglao I., 9°31.0′N, 123°40.8′E, 2–50 m, 5.vi.2004; 2 females SL 7.5–8.3 mm (ZRC), stn R23, lagoon off Poblacion, Panglao I., 9°33.5′/34.8′N, 123°42.7′/46.3′E, 1–5 m, 5, 6, & 21.vi.2004; 2 males SL 8.4–11.8 mm (ZRC), stn R29, Pontod Islet, Panglao I., 9°33.5′N, 123°42.6′E, 3–35 m, 7.vi.2004; 1 female SL 12.0 mm (ZRC), stn R31, Pamilacan I. south-southwest slope, 9°29.4′N, 123°56.0′E, 10–41 m, 8.vi.2004; 1 ovig. female SL 6.5 mm (ZRC), stn R36, Pamilacan I., 9°30.2′N, 123°55.3′E, 3–32 m, 9.vi.2004; 1 male SL 7.8 mm (ZRC), stn R38, Pamilacan I., 9°29.4′N, 123°56.0′E, 6–37 m, 11.vi.2004; 1 male SL 4.0 mm (ZRC), stn R58, Looc (lagoon side), Panglao I., 9°35.7′N, 123°44.7′E, 1–3 m, 22.vi.2004; 1 ovig. female SL 6.5 mm, 2 males SL 6.9–7.5 mm (ZRC), stn R71, Arco Point, Panglao I., 9°34.1′N, 123°48.9′E, 2–20 m, 1.vii.2004; 1 ovig. female SL 5.8 mm (ZRC), stn S15, Cortes Takot, Bohol I., 9°41.3′N, 123°49.5′E, 4–6 m, 16.vi.2004.
Description. Shield approximately 0.9 times as long as broad; anterior margin between rostrum and lateral projections shallowly concave; lateral margins slightly convex, with sparse tufts of long setae. Posterior margin rounded. Dorsal surface of shield somewhat inflated, with tufts of long setae, strongly calcified; Y-shaped line present posteriorly. Rostral lobe weakly produced. Lateral projections large, bluntly triangular, produced. Posterior carapace lateral elements well calcified, unarmed. Branchiostegites unarmed.
Ocular peduncles 0.9 times length of shield, longer than antennal and antennular peduncles, subcylindrical, somewhat inflated distally, diameter of corneas 0.2 length of ocular peduncles. Ocular acicles broad, distal margins each with 3 small spines, with fringe of setae along distal margins. Interocular plate with pair of protrusions.
Antennular peduncles slender, when fully extended, reaching base of corneas; ultimate and penultimate segments unarmed, basal segment distal margin with fringe of long setae.
Antennal peduncles when fully extended reaching 0.6 length of ocular peduncles; fifth segment unarmed, with 3–4 scattered setae on dorsal and ventral surfaces; fourth segment with tufts of setae on mesiodistal margin; third segment with tufts of long setae on ventral surface; second segment with dorsolateral distal angle produced, terminating in simple or bifid spine, lateral margin unarmed, dorsomesial distal angle unarmed or bearing 1 spine, mesial margin, lateral margin, and dorsolateral distal angle with tufts of setae; first segment with ventrolateral distal angle unarmed or with 1 spine, ventromesial distal angle produced, rounded. Antennal acicle terminating in bifid spine; dorsomesial margin with 3 spines, dorsolateral margin unarmed or with single small spine. Antennal flagella bearing minute seta on each articulation.
Third maxilliped with well developed crista dentata; basis with 1 or 2 small corneous spines, spines concealed by tufts of long setae.
Chelipeds unequal, left larger than right. Left cheliped stout. Outer face of palm, dactyl, and fixed finger convex; bearing irregular rows of corneous-tipped conical spines, with sparse short and long setae. Dactyl and fixed finger each terminating in strong corneous claw, cutting edges each with 3 large and 4 small (dactyl) or 2 large and 4 small (fixed finger) molar-like calcareous teeth. Upper margin and outer face of dactyl with row of corneous-tipped spines, with rows of tufts of long and short setae. Palm and fixed finger with rows of corneous-tipped spines accompanied by tufts of sparse setae; lower margin of palm with corneous-tipped spines, smaller spines proximally. Inner face of palm, dactyl, and fixed finger slightly convex with irregular rows of tufts of setae. Carpus with upper margin bearing 4 corneous-tipped spines; outer face slightly convex with irregular rows of corneous-tipped spines, distal outer face with transverse rows of small corneous-tipped spines; inner face with scattered tufts of setae particularly on the inner distal margin. Merus with row of spines on ventral margin; entire lateral face with tufts of long setae. Ischium with 3 teeth on ventromesial margin. Right cheliped more slender than left, armament similar to left.
Second pereopods and right third pereopod generally similar, but setation and armament slightly different between second pair and right third; second pair more slender than right third; of second pair, left slightly shorter than right. Dactyls all 1.6–1.7 length of propodi; each terminating in strong corneous claw; subcylindrical, with rows of setae on dorsal and ventral margins, and on median of lateral and mesial faces; dorsal margins each with row of spines; ventral margins each with 7 small corneous spines. Propodi 1.5 length of carpi; dorsal margins each with row of small corneous spines with sparse tufts of setae; ventral margins unarmed but with sparse tufts of setae; lateral faces convex, unarmed, and with rows of sparse tufts of setae; mesial faces flattened, smooth, unarmed, with sparse tufts of setae. Carpi 0.6–0.7 length of meri; dorsal margins with tufts of long setae, bearing 2 prominent corneous-tipped conical spines distally; distal margins each with row of transverse corneous-tipped spines and few tufts of setae. Meri lateral faces flattened, with tufts of setae on dorsal and ventral margins; ventral margins each with 2–3 corneous-tipped spines or unarmed. Ischia unarmed.
Left third pereopod stout. Dactyl 1.2 length of propodus, terminating in large corneous claw; lateral face flattened or concave, dorsal and ventral margins each with double rows of corneous spines accompanied by tufts of setae; mesial face convex, with tufts of long setae along median line. Propodus 1.4 length of carpus, 2.2–2.5 as long as broad; lateral face flattened, with longitudinal concavity on upper half; dorsal margin of lateral face with 2 irregular rows of sharp corneous spines; subventral 0.3 of lateral face with irregular rows of sharp corneous spines; mesial face convex, smooth, with rows of sparse tufts of long setae. Carpus 0.9 length of merus; dorsal margin with row of 4 corneous-tipped spines not concealed by tufts of setae; distal margin with transverse row of corneous-tipped spines, remaining of outer face with few spines. Merus lateral face flattened, with tufts of setae on dorsal and ventral margins; ventral margin with 2–3 corneous-tipped spines or unarmed. Ischia unarmed.
Sternite of third pereopods with anterior lobe rectangular, with 2 protrusions each bearing tuft of long setae anteriorly.
Fourth pereopods semichelate; dactyls each with 5 corneous ventral spines on lateral face; propodal rasps well developed; carpi each with sharp dorsodistal spine covered by tuft of long setae.
Fifth pereopods chelate; rasps of dactyl and propodus well developed.
Male pleon with first to fifth left pleopod fringed with sparse setae, uniramous. Female pleon with second to fifth left pleopods fringed with long setae; second to fourth triramous; fifth uniramous; single, large, elongate, triangular fleshy membrane fringed with long setae present between fourth and fifth pleopods.
Uropods strongly asymmetrical, left larger than right; endopods and exopods with well developed rasps.
Telson with lateral constrictions; marginal area partially calcified; posterior lobes separated by median cleft, left much larger than right, each with 7 (left) or 4 (right) ventral corneous spines near terminal margin, terminal margins fringed with long setae; anterior lobes with long setae on lateral margins.
Colour. Shield reddish brown, with small bright red or orange-and-blue patches on the antero-distal corners; posterior carapace mottled red and tan. Ocular peduncles uniform purplish brown, with narrow yellow line next to black cornea. Antennules and antennae yellowish brown. Chelipeds reddish purple with white tubercles, bright red or orange-and-blue patch on carpus; setae reddish purple with white tips. Pereopods 2 and 3 reddish purple; large bright red patch on carpus; setae reddish purple with white tips.
Habitat. Intertidal to subtidal, 0 to approximately 20 m deep, reef flats, seagrass beds, reef slopes, on coralline, sandy, and mud-sand substrates. Often collected from the same spot as D. lagopodes.
Remarks. The species D. sanguinolentus (Quoy & Gaimard, 1824) refers to the “red knee” form previously synonymised with D. lagopodes. The latter name is now restricted to the “blue knee” form. Dardanus sanguinolentus is distinguished morphologically from D. lagopodes by the presence of a deep sulcus on the upper half of the lateral face of the dactyl and propodus of LP3. The two species are also genetically distinct (Fig. 9). See further detailed remarks under D. lagopodes.
The geographic range of D. sanguinolentus broadly overlaps with that of D. lagopodes. While colouration is not always reported in checklists, D. sanguinolentus is known with certainty from the Red Sea, Réunion, Seychelles, Europa Island, Juan de Nova Island, Mayotte, Papua New Guinea, Indonesia, Vietnam, Philippines, Taiwan, Okinawa, Guam, Australia, New Caledonia, Fiji, and Society. This is the first time that D. sanguinolentus is formally reported from the Philippines as the species reported by Cassidy (2005) was under the name of D. lagopodes.
description: Published as part of Malay, Maria Celia (Machel) D., Rahayu, Dwi Listyo & Chan, Tin-Yam, 2018, Hermit crabs of the genera Calcinus Dana, Clibanarius Dana, and Dardanus Paul'son from the PANGLAO 2004 Expedition, with description of a new species and a checklist of the hermit crabs of the Philippines (Crustacea: Anomura: Paguroidea), pp. 23-65 in Raffles Bulletin of Zoology 66 on pages 43-44, DOI: 10.5281/zenodo.4503028