Patonia mclaughlina

Mitsuhashi, Masako & Chan, Tin-Yam, 2006, A new genus and species of deep-water pontoniine shrimp (Decapoda, Caridea, Palaemonidae) from Taiwan, Zoosystema 28 (2), pp. 389-398 : 391-397

publication ID	https://doi.org/ 10.5281/zenodo.5391363
persistent identifier	https://treatment.plazi.org/id/03AD87B9-FFE1-FFD0-1619-FAD2FEA41A65
treatment provided by	Marcus
scientific name	Patonia mclaughlina
status

Treatment

Patonia mclaughlina e n. sp.

( Figs 1-6 View FIG View FIG View FIG View FIG View FIG View FIG )

MATERIAL EXAMINED. — Holotype: Taiwan northeastern coast, TAIWAN 2003, R / V Ocean Researcher 1, stn CP 216, 24°34.71’N, 122°4.02’E, beam trawl, 209- 280 m, 27.VII.2003, 1 ovig. ♀ cl 4.0 mm, bl 18.2 mm ( NTOUM00664 ). GoogleMaps

ETYMOLOGY. — The specific name again honors Dr Patsy A. McLaughlin, in recognition of her important contributions to the knowledge of decapod crustaceans.

Mitsuhashi M. & Chan T.-Y.

DESCRIPTION

A small size shrimp with laterally compressed body.

Rostrum ( Figs 3 View FIG ; 4B View FIG ) well developed, laterally compressed, slightly curving down distally, just exceeding antennular peduncle; lateral carina well defined and continuous with orbital margin; dorsal border armed with eight distinct, evenly spaced teeth, posterior three teeth with indistinct basal suture; two postorbital teeth present, with distinct basal sutures; ventral border unarmed and convex.

Carapace ( Figs 3 View FIG ; 4A, B View FIG ) moderately compressed laterally, glabrous, epigastric and supraorbital spines absent; orbit well developed; inferior orbital angle strongly produced, blunt, slightly exceeding antennal spine; antennal spine well developed, submarginal; hepatic spine ( Fig. 2 View FIG ) large, at level much lower than antennal spine, with distinct basal suture, possibly movable; branchiostegite angle blunt, and not produced.

Abdomen ( Fig. 3 View FIG ) laterally compressed and smooth, about three times longer than carapace length; third tergite not posterodorsally produced; pleura broadly rounded; second pleuron greatly expanded in ovigerous female holotype, and covering almost entire third pleuron; sixth somite 1.5 times longer than fifth somite and 1.8 times longer than width, posterolateral and posteroventral angles acute. Telson ( Fig. 4D View FIG ) 1.2 times as long as sixth somite, four times longer than maximum width, tapering posteriorly; two pairs of dorsolateral spines situated at distal 1/2 and 1/4; posterior margin with minute median denticle, and three pairs of movable spines, intermediate pair largest, lateral pair smallest.

Antennular peduncle ( Fig. 4A, C View FIG ) extending to 2/3 of scaphocerite; proximal segment 2.3 times longer than width, with ventromedial tooth; distolateral angle strongly produced and bearing three acute teeth, extending beyond middle of intermediate segment; statocyst normally developed; stylocerite

A new pontoniine shrimp genus from Taiwan sharply elongate and overreaching half segment length; intermediate segment 3/4 times as long as distal segment and 0.36 times as wide as proximal segment; distal segment twice longer than broad; upper flagellum biramous, with proximal seven segments fused.

Antenna with distinct basicerite spine; carpocerite robust, 2.6 times longer than width, about 1/3 of scaphocerite length; flagellum about three times longer than carapace length; scaphocerite well developed, 3.7 times longer than broad, maximum width at proximal 1/3 of length, lateral margin straight, distolateral tooth large but falling far short of distal margin of lamella.

Eye ( Fig. 4A View FIG ) large, well developed; peduncle wider than long; cornea longer than wide, well pigmented.

Epistome unarmed. Thoracic sternites without projection; fifth sternite with low transverse ridge having wide median notch.

Mandible ( Fig. 5A View FIG ) normal, without palp; molar process distally setose and with six blunt teeth; incisor process obliquely truncate distally with three or four teeth, lateral teeth larger than medial teeth. Maxillula ( Fig. 5B View FIG ) with bilobed palp, lower lobe with stout hooked seta; upper lacinia with about 10 short stout spines and several setae distally, lower margin with long plumose setae; lower lacinia slen- der, tapering, densely packed with spiniform setae distally, lower and upper margins bearing plumose setae. Maxilla ( Fig. 5C View FIG ) with palp simple and bent, setose laterally; basal endite deeply bilobed, each with about 10 setae distally; coxal endite obsolete, medial margin convex; scaphognathite large, broad, 2.6 times longer than central width, anterior lobe with medial margin concave, posterior lobe broadly rounded. First maxilliped ( Fig. 5D View FIG ) with palp elongated and bearing one apical seta; basal endite rectangular, with distal and medial margins setose; coxal endite indistinct, medial margin sparsely setose; exopod bearing long flagellum with four long plumose setae at apex, caridean lobe large, broad; epipod large and bilobed. Second maxilliped ( Fig. 5E View FIG ) with normal endopod, dactylar segment narrow, with multiple rows of serrulate spines medially, propodal segment large, distomedial margin with several spinulate setae, upper margin and distomedial surface bearing some long setae; carpus, ischiomerus and basis normal, coxa produced medially and bearing two setae; exopod well developed and bearing four long plumose setae apically; epipod large, subrectangular; podobranch absent. Third maxilliped ( Fig. 5F View FIG ) with moderately slender endopod; ultimate segment tapering distally and densely setose medially; penultimate segment 0.45 length of proximal segment, about four times longer than width and densely setose medially; ischiomerus 4.5 times longer than broad, with three or four distolateral spines, medial margin distributed with long setae; separation between basis and ischiomerus obscure; basis bearing some long setae along medial margin; exopod not reaching penultimate segment, with four apical setae; coxa slightly produced medially and bearing one seta; arthrobranch reduced and with four lamellae.

First pereiopods ( Fig. 6A, B View FIG ) slender, reaching tip of scaphocerite; chela slender, 4.8 times longer than width, fingers slightly longer than palm; movable finger six times longer than proximal width, cutting edge entire, unarmed; fixed finger similar, 5.4 times longer than proximal width; both fingers provided with tufts of setae; palm scattered with setae, particularly with group of short setae proximomedially; carpus 1.5 times as long as chela and seven times longer than distal width, distally with tufts of plumose setae; merus as long as carpus, naked and smooth, 8.4 times longer than width; ischium 2.5 times as long as merus, three times longer than maximum width; basis short, 0.7 times as long as ischium; coxa with row of ventromedial setae.

Second pereiopods ( Fig. 6C, D View FIG ) similar, slender, overreaching scaphocerite by length of chela and distal 1/4 length of carpus; chela slender, shorter than half length of carapace, 5.7 times longer than width, ventral margin slightly concave; fingers slightly longer than palm, movable and fixed fingers similar, 6.3 times longer than proximal width, cutting edge entire, unarmed, with tufts of setae distally; carpus slightly broaden distally, unarmed, 1.2 times longer than chela and 8.7 times as long as distal width; merus naked and smooth, 0.8 times as long as carpus, same length as ischium, eight times as long as wide; ischium slender, unarmed, 9.3 times as long as distal width.

Third pereiopod ( Fig. 6E, F View FIG ) slender, not exceeding scaphocerite; dactylus short, 2.6 times as long as proximal width, biunguiculate, accessory tooth half length of demarcated unguis; propodus 7.6 times as long as dactylus, with four or five ventral spinules, distal margin bearing tufts of setae; carpus 0.56 times as long as propodus, five times as long as width, unarmed; merus 1.7 times longer than carpus, eight times as long as width; ischium 0.48 times as long as ischium, 3.7 times longer than width. Fourth and fifth pereiopods similar to third pereiopod.

Pleopods ( Fig. 4E, F View FIG ) slender; endopod of first pleopod 1/3 as long as exopod and about three times longer than wide, without appendix interna; exopod of second pleopod 1.2 times longer than endopod, appendix interna reaching distal 1/3 of endopod.

Uropods ( Fig. 4G View FIG ) with posterolateral lobe of protopodite blunt, unarmed; exopod well exceeding telson, broad, 3.3 times longer than maximum width, lateral border feebly convex and bearing minute distal spinule with larger movable spine medially; endopod shorter than exopod, 0.9 times as long as exopod, 3.7 times longer than wide.

Eggs about 0.46 mm in maximum length (few remaining in holotype).

Coloration ( Fig. 1 View FIG )

Body generally translucent and somewhat pinkish, lateral surface bearing three pairs of faint but broad pale red longitudinal stripes extending from carapace to fifth abdominal somite. Rostrum mottled with white dots. Eyes dark brown. Pereiopods generally translucent except for slightly pinkish chela of second pereiopod. Pleopods pale red. Distal part of uropods mottled with some white dots. Eggs greenish brown.

REMARKS

Patonia mclaughlinae n. gen., n. sp. can be distinguished from other known Pontoniinae in having the following combination of characters: body moderately compressed laterally; hepatic spine large, with a complete basal suture and possibly mobile; rostrum armed with distinct teeth along entire dorsal border; pereiopods slender, second pereiopod feebly developed with carpus distinctly longer than chela.

The general appearance of this new species shows some resemblance to Periclimenes perturbans Bruce, 1978 from Madagascar and Hong Kong ( Bruce 1990), and P. priodactylus Bruce, 1992 from Australia. However, these two species are found in shallow waters (3.5-40 m), and morphologically differ from P. mclaughlinae n. gen., n. sp. in having the hepatic spine much smaller, the rostral teeth fixed, and the basal segment of the antennular peduncle bearing only a simple distolateral tooth. Moreover, in P. mclaughlinae n. gen., n. sp., the carpi of the second pereiopods are shorter than the chelae, and the shape of the dactyli of the posterior pereiopods are different (simple in P. perturbans and densely serrated with ventral spinules in P. priodactylus ).

The present new species was collected from a station rich in crinoids, chirostylids, galatheids, hermit crabs and pylochelids. However, there was no direct evidence of the host of this shrimp.

Shrimps of the family Palaemonidae have greatest diversity in shallow tropical waters. Deep-water palaemonids (i.e. from more than 200 m deep) are much fewer in numbers and at present only 33 species of eight genera have been recognized ( Bruce 1991, 1996). The discovery of this new genus and species in Taiwan waters demonstrates again the high diversity of the marine environments of this island.