Chelarctus virgosus ( Yang and Chan, 2012 )

Ueda, Kenta, Yanagimoto, Takashi, Chow, Seinen, Kuroki, Mari & Yamakawa, Takashi, 2021, Molecular Identification of Mid to Final Stage Slipper Lobster Phyllosoma Larvae of the Genus (Crustacea: Decapoda: Scyllaridae) Collected in the Pacific with Descriptions of Their Larval Morphology., Zoological Studies 60 (75), pp. 1-21 : 4-8

publication ID	https://doi.org/ 10.6620/ZS.2021.60-75
persistent identifier	https://treatment.plazi.org/id/03FC87F3-FFC3-BD6A-4B06-FC4CE478FEAC
treatment provided by	Felipe
scientific name	Chelarctus virgosus ( Yang and Chan, 2012 )
status

Treatment

Chelarctus virgosus ( Yang and Chan, 2012) View in CoL

Stage V (KY18-1, Fig. 4 View Fig )

TL = 8.45 mm; CL = 5.73 mm; CW = 6.71 mm; TW = 3.50 mm; AL = 1.24 mm; CW/CL = 1.17; CW/ TW = 1.92. This description was completed for the specimen collected at 27°02'N, 142°05'E (offshore of the Ogasawara Islands) on 31 July 2018.

Cephalic shield ( Fig. 4A View Fig ): sub-pentagonal; slightly wider than long, nearly twice as wide as thorax. Antennule ( Fig. 4B View Fig ): biramous, 3-segmented; distal segment with two flagella (primary and accessory); primary flagellum unsegmented with 9 ‒ 10 rows of sensory setae, slightly shorter than accessory flagellum. Antenna ( Fig. 4B View Fig ): bifurcated, unsegmented, half H-shaped (├), exceeding antennule; short lateral process projecting horizontally. Maxillule 1 ( Fig. 4E View Fig ): anterior lobe with denticulate three strong setae; posterior lobe with denticulate two strong setae. Maxillule 2 ( Fig. 4C View Fig ): rudimentary flattened. Maxilliped 1 ( Fig. 4C View Fig ): rudimentary bud. Maxilliped 2 ( Fig. 4C, D View Fig ): 5-segmented, coxal spine absent; three short setae on dactylus; at least five long setae on proximal margin of propodus ( Fig. 4D View Fig ). Maxilliped 3 ( Fig. 4A View Fig ): 5-segmented, tiny ventral coxal spine; distal parts of propodus and dactylus setosed densely; exopod absent. Pereiopods 1‒4 ( Fig. 4A View Fig ): biramous, tiny coxal spine and 5-segmented endopod; ischio-merus fused to basis, one stronger and one smaller distal spines on outer and inner sides of ischio-merus; a tiny distal spine on carpus; a dense of setae covering ischio-merus. Pereiopod 5 ( Fig. 4F, G View Fig ): elongated bud, coxal spine absent, much shorter than abdomen. Abdomen ( Fig. 4F, G View Fig ): four pairs of undeveloped pleopod buds; slightly bilobed uropod, rounded posterior margin locating far anterior of central margin of telson; prominent posterolateral spines of telson far beyond posterior central margin of telson, more than three times the length of uropod.

Stage VI (KY15-1, Fig. 5 View Fig )

TL = 12.66 mm; CL = 7.96 mm; CW = 9.73 mm; TW = 4.58 mm; AL = 2.41 mm; CW/CL = 1.22; CW/ TW = 2.12. This description was completed for the specimen collected at 27°07'N, 142°05'E (offshore of Ogasawara Islands), on 30 January 2015.

Cephalic shield ( Fig. 5A View Fig ): more than twice as wide as thorax. Antennule ( Fig. 5B View Fig ): primary flagellum similar in length to accessory flagellum. Antenna ( Fig. 5B View Fig ): similar in length to antennule. Maxilliped 1 ( Fig. 5C View Fig ): cone-shaped buds. Maxilliped 3 ( Fig. 5A View Fig ): propodus more densely setose than stage V (at least 20 setae). Pereiopods 1−4 ( Fig. 5A View Fig ): coxal spines more developed than those during stage V. Pereiopod 5 ( Fig. 5F, G View Fig ): 2-segmented, shorter than half of abdomen. Abdomen ( Fig. 5F, G View Fig ): four pairs of unbilobed pleopods; bilobed uropods; posterolateral spines of telson twice as long as uropod.

Stage VII (SHU09-1, Fig. 6 View Fig )

TL = 18.61 mm; CL = 11.89 mm; CW = 14.11 mm; TW = 7.67 mm, AL = 4.66 mm; CW/CL = 1.18; CW/ TW = 1.84. This description was completed for the specimen collected at 25°30'N, 126°05'E (around the Ryukyu Archipelago) on 8 June 2009.

Antennule ( Fig. 6B View Fig ): accessory flagellum longer than primary flagellum; larger number of setae on primary flagella than during stage VI. Antenna ( Fig. 6B View Fig ): lateral process stouter than that of stage VI. Maxillule 2 ( Fig. 6C View Fig ): rudimentary bilobed. Maxilliped 1 ( Fig. 6C View Fig ): slightly biramous. Maxilliped 2 ( Fig. 6C, D View Fig ): four setae on dactylus; two long terminal setae on propodus with four short simple setae. Maxilliped 3 ( Fig. 6A View Fig ): exopod bud, at least 19 setae on propodus. Pereiopods 1−4 ( Fig. 6A View Fig ): more spine-like setae on basis surface than during stage VI; at least 26 setae scattered over the surface of the P1 propodus; P4 longer than other pereiopods. Pereiopod 5 ( Fig. 6F, G View Fig ): 3-segmented, tiny coxal spine, about half of abdomen. Abdomen ( Fig. 6F, G View Fig ): pleopod biramous; posterolateral spines slightly longer than uropod.

Stage VIII (SHU09-2, Fig. 7 View Fig )

TL = 20.66 mm; CL = 12.30 mm; CW = 15.97 mm;

TW = 7.76 mm; AL = 5.92 mm; CW/CL = 1.25; CW/ TW = 2.06. This description was completed for the specimen collected at 23°19'N, 126°09'E (around the Ryukyu Archipelago) on 9 June 2009.

Antenna ( Fig. 7B View Fig ): exceeding antennule. Maxillule 1 ( Fig. 7E View Fig ): six short terminal setae, two long denticulate setae and two normal terminal setae on the posterior lobe and two sub-terminal setae on the outer side of the posterior lobe. Maxillule 2 ( Fig. 7C View Fig ): apparently biramous, more developed posterior lobe than during stage VII. Maxilliped 1 ( Fig. 7C View Fig ): unsegmented and bilobed, outer lobe flattened and rounded. Maxilliped 2 ( Fig. 7C, D View Fig ): an exopod bud. Maxilliped 3: coxal spine absent; propodus more densely setose than stage VII. Pereiopods 1−4 ( Fig. 7A View Fig ): gill buds on base of coxa; at least 33 setae scattered over the surface of the propodus in P1. Pereiopod 5 ( Fig. 7F, G View Fig ): 4-segmented, much longer than half of abdomen. Abdomen ( Fig. 7F, G View Fig ): biramous pleopods larger than stage VII; round uropod margin near reaching but never exceeding posterior central margin of telson; posterolateral spines of telson similar in length of uropod.