Pilumnus hirtellus ( Linnaeus, 1761 )

Ng, Peter K. L., 2000, The Indo-Paci ® c Pilumnidae XII. On the familial placement of Chlorodiella bidentata (Nobili, 1901) and Tanaocheles stenochilus Kropp, 1984 using adult and larval characters with the establishment of a new subfamily, Tanaochelinae (Crustacea: Decapoda: Brachyura), Journal of Natural History 34, pp. 207-245 : 228-231

Pilumnus hirtellus ( Linnaeus, 1761)

(®gures 20a±c, 21a±c, 22a, b, 23a, b)

Pilumnus hyrtellus: Williamson, 1915: 490 , ®gs 314±316, 317 (zoea I, crab stage).

Pilumnus sp. : Williamson, 1915: 492, ®gs 318±319 (zoeas I, II).

Pilumnus hirtellus: Boraschi, 1921: 9 , tav. 1, ®g. 14 (zoea I); Lebour, 1928: 532, ®g. 1(18), pl. II, ®g. 5, pl. X, ®gs 6±8, pl. XI, ®gs 1±4 (prezoea, zoeas I±IV, megalop, crab 1); Bourdillon- Casanova, 1960: 172, ®g. 54 (prezoea, zoea I, crab 1); Salman, 1982: 113, ®gs 1±7 (zoeas I±IV, megalop); Ingle, 1983: 973, ®g. 15a, b, f (megalop, crab 1); Hong, 1988: 1019, ®g. 12 (zoeas I±IV, megalop); Ingle, 1991: 232 ±234, ®gs 1.13k, 1.18b, 1.23c, 1.25g, 1.29b, 1.32c, 1.34o, 1.36h, 1.38d, 2.30b±t (zoeas I±IV, megalop).

Material examined. England: Falmouth Harbour , Cornwall (zoea I, NHM, reg. no. 1998.600), hatched 4± 5 June 1975 , coll. R. Lincoln , 15 April 1975 .

Zoea I description. Carapace (®gure 20a): dorsal spine smooth, curved distally, approximately twice as long as rostral spine; rostral spine smooth, shorter than dorsal and antennal protopod; lateral spines short and unarmed; one pair of posterodorsal setae; ventral margin without setae, eyes sessile.

Antennule (®gure 20a, b): uniramous, endopod absent; exopod unsegmented with four terminal aesthetascs (2 broad and long, 2 shorter and slender) plus two terminal setae of unequal length.

Antenna (®gure 20a, c): protopod distally spinulate, longer in length than rostral spine but slightly shorter than exopod; endopod absent; exopod longer than protopod, unsegmented, distally spinulate with one long and one smaller medial setae unequal in length.

Mandible: endopod palp absent.

Maxillule (®gure 21a): coxal endite with seven setae; basial endite with ®ve terminal setal processes and two small teeth; endopod two-segmented, proximal segment with one seta; distal segment with six (2 subterminal +4 terminal) setae; exopod seta absent.

Maxilla (®gure 21b): coxal endite bilobed with 5 +4 setae; basial endite bilobed with 5 +4 setae; endopod bilobed with 3 +5 (2 subterminal +3 terminal setae); exopod (scaphognathite) margin with four setae and one long distal stout process.

First maxilliped (®gure 22a): coxa without setae; basis with 10 setae arranged 2,2,3,3; endopod ®ve-segmented with 3,2,1,2,5 (1 subterminal and 4 terminal setae) respectively; exopod two-segmented, distal segment with four long terminal plumose natatory setae.

Second maxilliped (®gure 22b): coxa without setae; basis with four setae; endopod three-segmented, with 1,1,6 (3 subterminal and 3 terminal) setae respectively; exopod two-segmented, distal segment with four long terminal plumose natatory setae.

Third maxilliped: absent.

Pereiopods: absent.

Abdomen (®gure 23a, b): ®ve somites; somite 2 with a pair of dorsolateral processes directed anteriorly; somite 3 with a pair of dorsolateral processes directed ventrally; somites 1±2 with rounded posterolateral processes and 3±5 with short posterolateral spinous processes; somite 1 without dorsal setae; somites 2±5 with one pair of posterodorsal setae; pleopod buds absent.

Telson (®gures 21c, 23a, b): each telson fork long, spinulate and gradually curved distally; one long and one small lateral spine; dorsal medial spine present; posterior margin with three pairs of stout spinulate setae.