Cumella levitergus, Lee, Chang-Mok & Lee, Kyung-Sook, 2012

Lee, Chang-Mok & Lee, Kyung-Sook, 2012, A new species and new record of the genus Cumella (Cumacea: Nannastacidae) from Korea, Zootaxa 3390, pp. 19-32 : 20-25

publication ID	https://doi.org/ 10.5281/zenodo.281757
DOI	https://doi.org/10.5281/zenodo.6173730
persistent identifier	https://treatment.plazi.org/id/03DB1A7A-3374-FFA0-FF04-FDDB372BD287
treatment provided by	Plazi
scientific name	Cumella levitergus
status	sp. nov.

Treatment

Cumella levitergus sp. nov.

( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Type material. Holotype: adult male, 2.7 mm, cat no. NIBRIV0000241827, Port Bongpo, Goseong-gun, Gangwon-do Prov., 38° 15ʹ 7ʹʹN, 128° 34ʹ 6ʹʹE, 8 June 1995, (C.Y. Chang) collected from light-trap on bottom, depth 3– 5m. Paratypes: 3 adult males, 2.6–2.7 mm, cat no. NIBRIV0000241828, data same as holotype; and the remaining paratypes, 11 adult males, 2.6–2.7 mm, dissected (appendages on one slide), DKU cat no. 201201, data same as holotype; in the collection of the authors.

Additional material examined: 4 males, same locality as type material, 23 February 2007, (Y.H. Kim) collected from light-trap on bottom, depth 3– 5m.

Etymology. The new species name levitergus is from the combination of the Latin words levis, meaning ‘smooth’, and tergus, meaning ‘back’, alluding to the smooth dorso-median carina of the carapace.

Diagnosis. Carapace covered with small, round, tightly arranged alveolate sculpturing; dorsomedian carina of carapace obsolete, not decorated; antenna 2 short, not extending beyond pleonite 4; uropod peduncle 1.65 times as long as pleonite 6, inner margin strongly serrated, with 1 short simple and 3–5 stout setae; uropod exopod 0.65 times as long as endopod.

Description. Holotype, adult male, 2.7 mm (excluding uropods), cat no. NIBRIV0000241827.

Body ( Figs. 1 View FIGURE 1 A, 4A, B) surface pitted, covered with abundant minute alveolate sculpturing.

Carapace ( Figs. 1 View FIGURE 1 A, B, 4D–F) 0.35 times as long as body length, twice as long as deep, 1.7 times as long as wide, dorsomedian carina smooth, not decorated; antennal notch concave; anterolateral margin rectangular, serrated faintly; pseudorostral lobes serrated faintly; ocular lobe broadly round, with 3 lenses.

Thorax ( Figs. 1 View FIGURE 1 A, B) 0.6 times as long as carapace length, 0.2 times as long as body length.

Abdomen ( Fig. 1 View FIGURE 1 A) 0.8 times as long as cephalothorax; pleonite 5 longest, 1.5 times as long as pleonite 6; lateral grooves formed on pleonite 1 to pleonite 3.

Antenna 1 ( Fig. 1 View FIGURE 1 C) peduncle triarticulate; first article 0.9 times as long as remaining articles combined, with 3 simple distal setae; second article with 3 simple distal setae on inner corner, outer corner with 3 sensory distal setae; third article equal in length to second one, with 1 simple medial seta, distal margin with 3 sensory setae and 1 simple seta; main flagellum triarticulate, with 1 aesthetasc and 1 long simple seta on inner corner, outer corner with 1 short simple seta; third article very minute, with 1 asthetasc and 1 simple long seta; accessory flagellum biarticulate, 0.65 times as long as first article of main flagellum, outer margin with 1 simple seta, terminal end with 1 sensory seta and 2 simple setae.

Antenna 2 ( Fig. 1 View FIGURE 1 D) short, not extending beyond pleonite 4; peduncle 5-articulate, second article with 1 plumose seta on inner margin.

Labium ( Fig. 1 View FIGURE 1 E) with numerous hairs on inner margin; apex of process with 3 spiniform setae.

Left mandible ( Fig. 1 View FIGURE 1 F) boat-shaped, with 5 pectinated setae between lacinia mobilis and pars molaris; pars incisiva with 3 teeth; lacinia mobilis with 4 indistinct teeth.

Right mandible ( Fig. 1 View FIGURE 1 G) with 6 pectinated setae between pars incisiva and pars molaris; pars incisiva with 4 teeth.

Maxilla 1 ( Fig. 2 View FIGURE 2 A) protopod with 11 spiniform setae on terminal margin, outer margin with 1 simple distal seta; endite with 1 simple seta, 1 pectinated seta, and 2 bifid setae on terminal margin.

Maxilla 2 ( Fig. 2 View FIGURE 2 B) protopod with 11 simple setae, 2 serrated setae, and 1 strong plumose seta on terminal margin, inner margin with 6 simple setae and 3 bifid setae.

Maxilliped 1 ( Fig. 2 View FIGURE 2 C) protopod inflated, carpus with 8 simple setae, 5 comb-shaped setae near inner margin, propodus serrated on outer margin; endite with 3 strong plumose setae, 3 simple setae and 1 bifid seta near inner margin, and 3 simple setae, 3 short setae and 1 specialized tooth near distal margin.

Maxilliped 2 ( Fig. 2 View FIGURE 2 D) basis 0.75 times as long as remaining articles combined, with 1 long plumose seta and several hairs on inner margin, 1 strong plumose seta on inner corner, and 2 short simple setae near distal margin.

Maxilliped 3 ( Fig. 2 View FIGURE 2 E) basis 1.25 times as long as remaining articles combined, inner margin serrated, with numerous hair-like setae, outer corner inflated, reaching to about 1/2 point of merus, with 2 long plumose setae and 1 short simple seta.

Pereopod 1 ( Fig. 3 View FIGURE 3 A) basis 0.9 times as long as remaining articles combined, with 1 simple seta and numerous hair-like setae on inner margin, outer margin with 2 rows of flattened hyaline teeth and plumose seta; carpus 2.2 times as long as dactylus, with 3 simple setae on inner margin, outer margin with numerous hair-like setae, 2 plumose medial setae, and 1 simple distal seta.

Pereopod 2 ( Fig. 3 View FIGURE 3 B) basis 1.5 times as long as remaining articles combined, with 1 plumose distal seta, serrated near inner corner, outer margin with 2 rows of flattened hyaline teeth, 1 simple distal seta; dactylus 1.15 times as long as carpus, with 4 simple setae on surface, and 2 short and 1 long setae terminally.

Pereopod 3 ( Fig. 3 View FIGURE 3 C) basis 1.5 times as long as remaining articles combined, with 2 rows of hyaline flattened teeth; outer margin with numerous hairs proximally, 1 plumose distal seta.

Pereopod 4 ( Fig. 3 View FIGURE 3 D) basis 1.1 times as long as remaining articles combined.

Pereopod 5 ( Fig. 3 View FIGURE 3 E) basis 0.6 times as long as remaining articles combined.

distribution C. levitergus sp. nov. C. sadoensis C. morion C. indosinica C. siamensis (male) (male) (female) (male) (male) Body length 2.6–2.7mm 2.5mm 1.5mm 3 mm 2–2.25 mm

Alveolate small and round large and irregular large and round??

sculpturing of the shaped, tightly shaped, tightly arranged shaped, rarely carapace arranged arranged

Dorsomedian carina obsolete, not developed, with 2 rows developed, with 2 obsolete, not obsolete, not of carapace decorated of serrations rows of serrations decorated decorated

Length of antenna 2 not extend past not extend past pleonite? extend past not extend past pleonite 4 1 pleonite 6 pleonite 3

Serration on distal

inner margin of basis absent absent? faint strong of pereopod 1

Number of inner seta

on carpus of 3 3? 2 1 (very short) pereopod 1

Relative length of

dactylus to carpus in dactylus> carpus dactylus = carpus? dactylus <carpus dactylus <pereopod 2 carpus

Number of inner

seta of uropod 3 3 2 5 7 endopod

Length of uropod 0.65 times as long as 0.50 times as long as 0.65 times as long 0.62 times as 0.75 times as exopod endopod endopod as endopod long as endopod long as endopod Distribution Korea (present Korea (Lee & Lee, California (Watling Vietnam Vietnam study) 2001), Japan (Gamô, & McCann, 1997) (Zimmer, 1952) (Zimmer, 1952) 1962)

Uropod ( Figs. 3 View FIGURE 3 F, 4C) peduncle 1.65 times as long as pleonite 6, inner margin strongly serrated, with 1 short simple and 5 stout setae, outer margin serrated faintly; endopod uniarticulate, 0.65 times as long as peduncle, inner margin serrated, with 3 short stout setae, outer margin serrated faintly, several sensory hair-like setae near middle portion, terminal margin with 1 short simple and 2 strong setae; exopod biarticulate, 0.65 times as long as endopod, second article with 1 simple inner seta and 2 terminal setae (one of them very long, much longer than exopod length).

Female, not known.

Remarks. Cumella levitergus is very similar to C. sadoensis Gamô, 1967 and C. morion Watling & McCann, 1997 in that the carapace is pitted and covered with abundant alveolate sculpturing. Also, C. levitergus resembles C. indosinica Zimmer, 1952 and C. siamensis Zimmer, 1952 in having the dorsomedian carina of the carapace obsolete, with no spines or teeth. The new species can be distinguished from related species by the combination of the following features and Table 1: 1) the alveolate sculpturing of the carapace is round, small, and tightly arranged in C. levitergus , while in C. sadoensis it has much larger units and in C. morion the sculpturing is rare and larger than in C. levitergus ; 2) the dorsomedian carina of the carapace is obsolete and not decorated in C. levitergus , C. indosinica and C. siamensis , while it is decorated with 2 rows of serrations in C. sadoensis and C. morion ; 3) the flagellum of the male antenna 2 does not extend past the posterior border of the pleonite 4 in C. levitergus , while in C. indosinica it extends past the pleonite 6, in C. sadoensis it does not extend past the pleonite 1, and in C. siamensis it does not extend past the pleonite 3; 4) in C. indosinica and C. siamensis the basis of the pereopod 1 is serrated near distal inner margin, while it is smooth in C. levitergus and C. sadoensis ; 5) the carpus of the pereopod 1 has 3 setae on the inner margin in C. levitergus and C. sadoensis , while it has 2 setae in C. indosinica and 1 seta (very short) in C. siamensis ; 6) the carpus of pereopod 2 is shorter than the length of the dactylus in C. levitergus , while it is subequal in length to the dactylus in C. sadoensis and longer than the dactylus in C. indosinica and C. siamensis ; 7) the uropod endopod has 3 inner setae in C. levitergus and C. sadoensis , while it has 5 setae in C. indosinica and 7 setae in C. siamensis ; 8) the uropod exopod is 0.65 times as long as the exopod in C. levitergus , while it is 0.5 times as long as the endopod in C. sadoensis , 0.62 times the endopod in C. indosinica and 0.7 times the endopod in C. siamensis .