Periclimenaeus rastrifer Bruce, 1980

Li, Xinzheng, Bruce, Alexander J. & Manning *, Raymond B., 2004, Some Palaemonid Shrimps (Crustacea: Decapoda) From Northern South China Sea, With Descripitions Of Two New Species, Raffles Bulletin of Zoology 52 (2), pp. 513-553 : 538-539

Periclimenaeus rastrifer Bruce, 1980

( Fig. 25 )

Periclimenaeus rastrifer Bruce, 1980: 27-33 , Figs. 12 , 13 A B ; 1982a: 267, Fig. 21 ; 2003: 224; Müller, 1993: 61; Li, 2000: 133, Fig. 159.

Material examined. – 1 female, CN X6 B-26, [19º45’N, 107ºE], 42m, muddy sand, AT, coll. Z. Fan,? Dec.1959 ; 2 males 1 female, CN K171 B-79B, [20º15’N, 108ºE], sand, 54m, AT, coll. F. Sun, 21 Jan.1959 ; 1 male CN X167 B-13B, [19º30’N, 107ºE], 47m, AT, coll. F. Sun, 15 Jan.1959 ; 1 male 6 females (3 ovig) 2 juv. ( IOCAS), 1 ovig female ( ZRC), CN X249 B-51B, [19º30’N, 107ºE], 52m, AT, 22 Aug.1962 ; 1 ovig female, CN K213 B-112, [19º30’N, 107ºE], muddy sand, 49.6m, AT, coll. Z. Fan, 7 Jul.1960 ; 2 females (ovig), CN K233 B-91B, [19ºN, 106º30’E], 42m, AT, coll. Z. Fan, 9 Jul.1960 ; 1 male 1 female (ovig), CN K224 B-24, [19ºN, 106º15’E], sand, 35m, AT, coll. Z. Fan, 9 Jul.1960 .

Diagnosis. – Very small pontoniie shrimp. Rostrum with 5- 6/0 teeth. Carapace without supraorbital tubercle or spine. Telson with 2 pairs of long dorsal spines, anterior pair placed close to anterior margin, posterior pair at about midway between anterior pair and posterior margin; lateral pair of posterior marginal spines small, intermediate and submedian pairs subequal in length to dorsal spines. Scaphocerite relatively elongate, with distolateral spine almost reaching distal margin of lamella. First pereiopods with fingers spatulate, distally denticulate, distinctly shorter than palm. Second pereiopods with major pereiopod with numerous small acute tubercles on merus and ischium, and minor pereiopod with the tubercles only on middle portion of merus; fixed finger of major chela with large acute tooth proximately. Dactyls of ambulatory pereiopods biunguiculate, corpus with well developed distal accessory tooth and series of acute 5- 6 ventral denticles. Uropods with 1 movable lateral spine on exopod.

Distribution. – Previously recorded from New Caledonia (type location), Hong Kong, and Queensland.

Remarks. – Periclimenaeus tchesunovi Duris, 1990 is very similar to this species. Duris (1990: 619) remarked the differences between the two species as: 1). rostral lamina deeper, not tapering distally, rostral formula is 6/ 1 in P. tchesunovi ; rostrum tapering distally, rostral formula is 7/ 0- 1 in P. rastrifer ; 2). Chelae of first pereiopods longer, fingers occupying about 0.33 of their length in P. tchesunovi ; fingers longer than half length of chela in P. rastrifer ; 3). Dactyl and palm of major second chela shorter and deeper, ratio of length to depth respectively 1.8:1 or 1.7: 1 in P. tchesunovi ; the ratios in P. rastrifer are 2.3:1 for both the segments. According to the illustrations of Duris (1990: Fig. 2A ) and Bruce (1982a: Figs. 21A, B ), it is difficult to decide in which species the rostral lamina is deeper; although the chela of the first pereiopod in P. rastrifer ( Bruce, 1982a: Fig. 21C ) looks deeper than that of P. tchesunovi ( Duris, 1990: Fig. 2G ), the ratio of the fingers to palm of both species is similar; ratios of length and depth in dactyl and palm of major second chela in both species are also similar according to the illustrations provided ( Duris, 1990: Fig. 2I ; Bruce, 1982a: Fig. 21D ). In our material, the rostral formula is 5-6/0, average dorsal teeth of 16 available specimens is 5.6; the ratio of finger to chela of first pereiopod is 0.35-0.45, average in 14 available specimens is 0.40; the ratio of length to depth of dactyl of major second pereiopod is 1.60-1.96, the average in 11 available specimens is 1.81; that of palm of major second pereiopod is 1.87-2.23, the average in 11 available specimens is 2.02. These characters of our material are intermediate between those of P. rastrifer and P. tchesunovi , the other characters are very similar in both species, except the apical teeth of fingers of first pereiopod, which is so fine that it is difficult to be used for distinguishing the two forms. It is not impossible that the two forms are synonymous.

Figures

Fig. 25. Periclimenaeus rastrifer Bruce, 1980. a, carapace and anterior appendages, lateral view; b, scaphocerite; c, 1st pereiopod; d, major 2nd pereiopod, outer view; e, same, fingers, inner view; f, minor 2nd pereiopod, outer view; g, telson and uropod, dorsal view.

Fig. 12. Palaemon sewelli (Kemp, 1925). a, carapace and rostrum, lateral view; b, left mandible; c, right 2nd pereiopod; d, right 3rd pereiopod.

Fig. 13. Urocaridella antonbruuni (Bruce, 1967). a, carapace and rostrum, lateral view; b, mandible; c, thoracic pleuron 3-8, lateral view, show the pleurobranchiae; d, 3rd maxilliped; e, 1st pereiopod; f, 2nd pereiopod; g, abdomen, lateral view; h, telson and uropod, dorsal view; i, tip of telson, dorsal view.

Fig. 21. Paranchistus liui, new species. a, body, lateral view; b, anterior region of carapace and rostrum, lateral view; c, carapace and anterior appendages, dorsal view, d, eye.

Fig. 2. Exopalaemon orientis Holthuis, 1950. a, carapace and rostrum, lateral view; b, mandible; c, 1st pereiopod; d, 2nd pereiopod; e, 3rd pereiopod; f, same, dactyl and propodus; g, 5th pereiopod; h, same, dactyl and propodus.