Curtipleon chadi, Stępień, Anna & Błażewicz-Paszkowycz, Magdalena, 2013

Stępień, Anna & Błażewicz-Paszkowycz, Magdalena, 2013, Four new species and two new genera of Metapseudidae (Crustacea: Tanaidacea: Apseudomorpha) from Australian coral reefs, Zootaxa 3717 (4), pp. 559-592 : 569-577

Curtipleon chadi n. sp.

Figs 5–9

Material examined: Holotype, female (MTQ W34235), HI 10-55B, 23°26'59.35"S 151°54'45.18"E, Heron I., Channel between Heron Island and Wistari Reef, reef channel, small coral rubble and sand, depth 30 m, 25 November 2010, coll. C. Buxton & M. Błażewicz-Paszkowycz. Allotype, male (MTQ W 34236), HI 10-55A, 23°26'59.35"S 151°54'45.18"E, Channel between Heron Island and Wistari Reef, reef channel, large coral rubble, depth 30 m, 25 November 2010, coll. C. Buxton & M. Błażewicz-Paszkowycz. Paratypes, 4 females (MTQ W 34237), HI 10-55B, the same locality; 5 females (MTQ W 34238), HI 10-55A, the same locality; 1 female (MTQ W 34239), HI 10-009E, 23°25'53.76"S 152°2'57.48"E, Sykes Reef W, coral rubble on sand, reef slope, depth 12 m, 14 November 2010, coll. C. Buxton; 1 female (Reg.), HI 10-31B, 23°15'44.28"S 151°55'32.16"E, Broomfield, back reef, coral rubble in bommie crevasse, depth 6.5 m, 17 November 2010, coll. C. Buxton; 1 female (MTQ W 34241), HI 10-19B, 23°35'35.52"S 15°23'55.80"E, Lamont Reef SE, reef wall, coarse sand and rubble at base of wall, depth 28 m, 15 November 2010, coll. M. Błażewicz-Paszkowycz & C. Buxton.

Diagnosis. Frontal margin of carapace concave, smooth with one central spine and small spines on lateral edge. Antennule peduncle article 1 with numerous inner spines; distal process well-developed with strong spines. Antenna article 1 with large and heavily serrated process; article 2 with two or three spines on each of margins; cheliped basis with strong apophysis and disto-medially with prominent, distally serrated apophysis. Pereopods 1 to 6 basis dorsal margin with a few blunt apophysis; pereopods 1 to 3 three times as long as wide, with two rows of six ventral spines; maxillule palp with five setae; uropod endopod with five segments.

Etymology. The species is named after Chad Buxton, who kindly helped to collect and sort the tanaidaceans in the field.

Description of female. Body ( Figs 5 A, B) 2.1 mm long, 3.3 times as long as wide, strongly calcified. Carapace 25% of total body length, with median carina bifurcating to reach antennule insertion; anterior margin concave, smooth, with small, central spine and minute lateral spines; eye lobes present, eye with dark pigment. Pereon tapering from anterior to posterior; pereonite 1 0.3 times as long as wide, with median ridge, and with seven apophyses along anterior margin; pereonites 2 and 3 similar in length, with seven apophyses along anterior margin and two on posterior margin; pereonite 4 longest, 1.3 times as long as pereonite 3, with four apophyses along anterior margin, four apophyses in posterior half, and three median, red spots; pereonite 5 0.6 times as long as pereonite 4, disposition of apophyses as on pereonite 4; pereonite 6 shortest, 0.5 times as long as pereonite 5, with four apophyses.

Antennule ( Fig. 8 A) peduncle article 1 robust, 3.4 times as long as wide, with three strong, acute spine-like apophyses on outer margin and rows of spines along article, distal margin with robust spinose apophysis and three plumose setae; article 2 1.2 times as long as wide, 0.3 times as long as article 1, with one simple and one penicillate seta distally; article 3 much narrower, 0.3 times as narrow as article 2; article 4 with one simple and one plumose setae on outer margin; outer flagellum with 5 segments; segments 1, 2 and 3 each with three simple setae and one aesthetasc distally; segment 4 with one simple distal seta; segment 5 with six simple distal setae; inner flagellum with three segments; all segments with two or three simple distal setae.

Antenna ( Fig. 8 E) with five-articulated peduncle; article 1 square, with large rounded and heavily serrated distally process; article 2 almost twice as long as wide, with two spines on outer margin, and with three spines accompanied with two fine setae on inner margin; article 3 0.3 times as long as article 2, with one penicillate seta on outer margin; article 4 half as long as article 2, with one penicillate seta on inner distal corner; article 5 little shorter than article 4, with four penicillate setae distally; flagellum with one tiny segment, bearing two fine, simple setae

Mouthparts. Labrum ( Fig. 7 F) rounded, naked. Right mandible ( Fig. 7 D) incisor with four blunt teeth, setiferous lobe with four trifurcate setae, molar ( Fig. 7 C) serrated distally; palp ( Fig. 7 A) three-articled; article 1 robust, with five dents and simple seta on inner margin and with two spines and one simple setae distally; article 2 with two rows of pinnate lateral setae and one simple subdistal seta; article 3 with row of pinnate setae along inner margin and with single distal seta. Left mandible ( Fig. 7 B) with crenulated outer margin and with row of five trifurcated setae and three simple setae on setiferous lobe, lacinia mobilis armed with four teeth. Maxillule ( Fig.

7G) inner endite with five plumose setae distally; outer endite with nine spines, with both margins finely setullated; endites with minute setae on both margins; palp ( Fig. 7 J) with two articles, distal article tipped with five terminally serrated setae. Maxilla ( Fig. 7 H) outer lobe of moveable endite with five simple setae distally and two strong simple setae subdistally; inner lobe of moveable endite with several simple setae distally and two strong simple setae subdistally; outer lobe of fixed endite with six simple setae and three leaf-shaped setae distally and one subdistal plumose seta; inner lobe of fixed finger with six plumose distal setae and with row of about 25 simple subdistal setae. Epignath ( Fig. 7 E) with long, plumose seta distally and four short, simple setae subdistally. Maxilliped ( Fig. 7 I) palp article 1 with two fine setae in outer distal corner; article 2 with outer margin serrated and with one fine seta in outer distal corner, inner margin crenulated, with numerous simple setae and blunt, short spines; article 3 with two rows of strong, simple setae on inner margin; article 4 with eight plumose setae distally and five subdistally; endite ( Fig. 7 K) with four couling-hooks and nine plumose setae on inner margin and simple setae along outer margin, and with five spines and four bifurcate setae distally, and two long plumose setae subdistally.

Cheliped ( Fig. 8 C) basis 1.6 times as long as wide ventral margin with four apophysis, dorsal margin with four apophysis and seven small spines; dorsodistal margin heavily serrated and supported with strong spinose process; exopodite absent; merus quadrangular, with four spines and six fine setae on ventral margin; carpus three times as long as wide, with three simple ventral setae, and one simple dorsodistal seta; propodus half as long as carpus, with one simple ventral seta and three simple setae on dorsal margin; fixed finger 0.75 times as long as propodus, with six fine ventral setae and with four fine median setae, cutting edge serrated, with six fine setae; dactylus with fine seta dorsally, and two simple setae near unguis; unguis 0.1 times as long as dactylus.

Pereopod 1 ( Fig. 9 A) basis 4.7 times as long as wide, with eight simple setae along ventral margin, and with four small and four large rounded linguiform apophyses, interspersed with simple setae on dorsal margin; ischium half as long as wide, naked; merus 2.3 times as long as wide, with three fine setae and one pinnate spine ventrally, and with fine seta on dorsal margin; carpus 1.2 times as long as merus, with two rows of six pinnate spines and two pinnate setae, and with three fine setae dorsally; propodus ( Fig. 9 A’) similar in length to carpus, with two parallel rows of six and five respectively pinnate spines and with three plumose distal setae, two fine and one penicillate dorsal setae and tuft of pinnate setae distodorsally; dactylus half as long as propodus, with two simple dorsal setae and two simple ventral setae accompanied with apophysis.

Pereopod 2 ( Fig. 9 B) basis 5.2 times as long as wide, with four fine ventral setae and with six small and three large linguiform apophyses, interspersed with simple setae dorsally; ischium 0.7 times as long as wide, with fine seta ventrally; merus almost twice as long as wide, with four fine setae and one pinnate ventral spine and with two fine dorsal setae; carpus 1.3 times as long as merus, with five pinnate spines and two plumose setae on ventral margin, and with five simple dorsal setae; propodus similar in length to carpus, 2.6 times as long as wide, with six pinnate spines, three fine and one plumose ventral setae, and with two simple and one penicillate seta on dorsal margin as well as with two simple setae, near dactylus insertion; dactylus as on pereopod 1, but only one fine ventral seta.

Pereopod 3 ( Fig. 9 C, C’) similar to pereopod 2.

Pereopod 4 ( Fig. 9 D) basis 4.3 times as long as wide, with five simple and one penicillate seta on ventral margin, and with three large and one small blunt apophyses interspersed with simple setae, and three proximal penicillate setae on dorsal margin; ischium 0.6 times as long as wide, naked; merus almost twice as long as wide, with three simple setae and one pinnate spine ventrally, and with one simple seta dorsally; carpus 1.7 times as long as merus, with eight pinnate spines and four simple setae ventrally, and with two simple setae dorsally; propodus ( Fig. 9 D’) similar in length to carpus, four times as long as wide, with six pinnate spines and six simple setae ventrally, and with one simple seta and one penicillate seta dorsally, and with tuft of pinnate setae distodorsally; dactylus as on pereopod 1.

Pereopod 5 ( Fig. 9 E) basis 5.7 times as long as wide, with five blunt apophyses and with seven fine ventral setae, one simple and three proximal penicillate setae on dorsal margin; ischium 1.3 times as long as wide, with two fine ventral setae; merus 2.2 times as long as wide, with two fine setae and two spines ventrally; carpus twice as long as merus, with six pinnate spines and four fine setae on ventral margin and with two simple dorsal setae; propodus 1.2 times as long as carpus, 4.2 times as long as wide, with five pinnate spines and four simple setae along ventral margin and with four simple and one penicillate seta along dorsal margin; dactylus as on pereopod 3.

Pereopod 6 ( Fig. 9 F) similar to pereopod 5, but two dorsal seta on dactylus.

Uropods ( Fig. 8 E) uniramous; basis 1.8 times as long as wide, endopod with five segments, segment 4 with two simple setae distally; segment 5 with four fine terminal setae.

Description of male ( Fig. 6 A, B) body similar to that of female, 2.5 mm long; antennule similar to that of female, but peduncle with fewer spines, and proximally-crenulated inner margin; cheliped ( Fig. 8 D) larger, with only three spines on carpus.

Distribution: Known only from the southern part of the Great Barrier Reef from the vicinity of Heron Island, in depths from 6 to 30 m, from coral rubble and coarse sand.

Remarks. Curtipleon chadi n. sp. is the fifth member of the genus and the second species collected in Australian waters. The new species can be distinguished from the other members by its having five segments in the endopod of the uropods ( Table 3 ). From C. loerzae , occurring in the East Australia, C. chadi differs by having numerous strong spines on the proximal peduncle article of the antennule and only a few strong spines on article 2 of the antennule. Additionally, C. chadi has an acute process in the distal part of the cheliped basis, which is not observed in any other species. Strong calcification of the cheliped may obstruct the observation of this feature; if only this process is absent in all other species it is a valuable species-specific character.

Diagnosis. Body dorso-ventrally flattened, 6.5 times as long as wide. Eyes present. Pereonites wider than long. Pleon of one free pleonite and pleotelson. Antennule basis serrated, outer flagellum of three and inner of two segments. Antenna reduced, of two articles only; distal article rudimentary. Female cheliped slender, without exopodite. Pereopods 1 to 3 with hook-like apophyses on basis and serrated dorsal margin of carpus. Pereopods 4 to 6 propodus ventral margin with two simple setae. Pleopods absent. Uropod biramous. Male similar to female, but cheliped robust, and carpus of pereopod 1 dorsally expanded and hirsute.

Type species: Creefs heronum n. gen n. sp. by monotypy

Gender: masculine

Etymology. The name refers to the program Census of Coral Reef Ecosystem ( CReefs ) being a part of the Census of Marine Life (CoML) program, during which the type species was collected.

Remarks. With only one free pleonite Creefs n. gen. fits the subfamily Synapseudinae . At first glance Creefs n. gen. is most similar to Vicinisyndes Gutu, 2007 , to which it is probably closely related ( Table 4 ). The most striking character of the new genus is the biarticulated peduncle of the antenna, while that of Vicinisyndes consists of five articles. In addition, the new genus has serrated inner margins of the antennules, these being apparently smooth in Vicinisyndes , and it has a wide, dorsally serrated carpus on pereopods 1 to 3, while in Vicinisyndes these are apparently simple and slender. Additionally, Creefs has two simple setae on the ventral margin of the propodus of pereopods 4 to 6 in contrast to the spines present there in Vicinisyndes .

character Cryptapseudes Curtipleon Synapseudes Vicinisyndes Creefs

Figures

FIGURE 5. Curtipleon chadi n. sp., holotype female. A body dorsal view; B body lateral view. Scale line = 1 mm.

FIGURE 6. Curtipleon chadi n. sp., allotype male. A body dorsal view; B body lateral view. Scale line = 1 mm.

FIGURE 7. Curtipleon chadi n. sp. A mandibular palp; B left mandible; C molar process; D right mandible; E epignath; F labrum; G maxillule; H maxilla; I maxilliped; J maxillipedal endite; K palp of maxillule. Scale line = 0.1 mm.

FIGURE 8. Curtipleon chadi n. sp. A antennule (female); B antennule (male); C cheliped (female); D cheliped (male); E uropod;

FIGURE 9. Curtipleon chadi n. sp. A pereopod 1; A’ propodus of pereopod 1; B pereopod 2; C pereopod 3; C’ propodus of pereopod 3; D pereopod 4; D’ propodus of pereopod 4; E pereopod 5; F pereopod 6. Scale line = 0.1 mm.

Tables

TABLE 3. Comparison of morphological features distinguishing between members of the genus Curtipleon.

character	C. carinatum	C. carinatoides	C. chadi	C. heterochelatum	C. loerzae
rostral concavity	smooth with central tooth and two strong spines on sides	with small tubercles	smooth with central tooth and minute spines on sides	with minute tubercles	smooth
antennule basis	strongly spinose	?	strongly spinose	strongly spinose	weakly spinose
antennule flagella segments	5-4	5-4	5-3	4-3	5-3
antenna flagellum distal segment	?	absent?	minute	large	minute
antenna peduncle article 2 spination	no spines?	dense strong	scarce strong	dense minute	no spines
no. of setae on dactylus of pereopods 1-6	?	1	2	1	1-2
cheliped carpus length/ width	3.5	5	3	5	2.5
cheliped basis distal process	?	?	present	absent	absent
cheliped basis dorsal spination	unarmed	dense	scarce	scarce	scarce
pereopod basis dorsal spination	?	?	blunt	sharp	blunt
uropod endopod articles	3	3	5	3	3
Genus Creefs n. gen.