Kupellonura tamago, Kakui, 2022

Kupellonura tamago View in CoL sp. nov.

[New Japanese name: Tamago-haranaga-uminanafushi]

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

Zoobank: urn:lsid:zoobank.org:act:E4E7C71C-DA76-486F-98B3-2256ABA69AC3

Etymology. The specific name is derived from the Japanese noun tamago (“egg”), referring to the oval shape of uropodal exopod.

Diagnosis. Eyes present. Telson margins smooth. Length of antennular flagellum article 2, 2.50 times width. Margins of uropodal endopod smooth, without serrations. Length of uropodal exopod 1.47 times width, oval, widest at proximal third; inner margin smooth, without serration or crenulation; outer margin not concave.

Type material. Holotype:female without oostegites ( SMBL-V0638 , 14 slides and 1 vial; body length 6.79 mm, body width 0.44 mm, head length 0.38 mm, head width 0.38mm,eye length 0.04mm); 34°57.091’N

140°07.774’E to 34°57.404’N 140°07.626’E, Stn.KG-4, off the southern coast of the Boso Peninsula , Japan, Northern Pacific, 445– 407 m depth; 17 November 2003; collected by M. Shimomura. GoogleMaps

Description of female holotype. Body length ( Figs. 1 View Figure 1 , 2A–E View Figure 2 )15.31 times body width, slender, without dorsal pigmentation in fixed specimen.Head length ( Fig.2A View Figure 2 ) 1.00 times head width; rostrum protruding as much as anterolateral lobes; eyes dorsolateral, small; length ratio of eye to head, 0.04. Pereonites 1–7 ( Fig. 2A–C View Figure 2 ) with length ratio 1.00:1.22:1.25:1.65:1.74:1.74:1.57. Pleonites 1–6 ( Fig. 2D View Figure 2 ) articulated, with length ratio 1.00:1.04:0.99:0.93:1.08:0.93; combined length pleonites 1–6, 0.19 times body length; pleonites 1–4 with several lateral plumose setae. Telson ( Fig. 4H View Figure 4 ) oval, margins smooth, with simple seta laterally and 16 distal simple setae.

Antennula ( Fig. 2F View Figure 2 ) with three peduncular articles and four flagellar articles. Peduncular article 1 longest, with outer simple seta; article 2 with 2 outer distal plumose sensory setae, and 1outer distal, 1mid-dorsal, and 1 inner distal simple seta; article 3 with 5 distal simple setae. Flagellar article 1 with distal plumose sensory seta; article 2 length 2.50 times width, naked; article 3 naked; article 4 with 2 outer distal simple setae and prominent aesthetasc.

Antenna ( Fig.2G View Figure 2 ) with 5 peduncular articles and 8 flagellar articles. Peduncular article 1 naked; article 2 with 2 distal and 1 inner middle simple seta; article 3 with 2 inner distal simple setae; article 4 with 1 outer and 1 distal plumose sensory seta and 2 distal simple setae; article 5 with one outer and 1 distal plumose sensory seta, and 1 inner middle and 3 distal simple setae. Flagellar articles 1–8 with 0, 3, 4, 4, 3, 4, 3, and 5 distal simple setae, respectively.

Mandible ( Fig. 2H View Figure 2 ) with tri-articulate palp. Palp article 1 with distal simple seta; article 2 longest, with distal simple seta; article 3 with 3 distal spiniform setae. Incisor with 2 cusps; lamina dentata with 2 teeth, molar rounded.

Maxilla ( Fig. 2I View Figure 2 ) with 1 strong and 5 smaller distal teeth.

Maxilliped ( Fig. 2J View Figure 2 ) with 5-articulate palp. Palp article 1 naked; article 2 with inner distal simple seta; article 3 with 3 distal simple setae; article 4 with 2 distal simple setae; article 5 with 4 distal simple setae. Endite overreaching distal margin of palp article 2, with distal simple seta and distal seta (tip broken).

Pereopod 1 ( Fig.3A View Figure 3 )subchelate, robust. Basis with ventrodistal simple seta. Ischium with 1 dorsal and 1 ventrodistal simple seta. Merus with 2 dorsodistal and 3 ventrodistal simple setae.Carpus triangular, not produced ventrodistally, with 1 ventroproximal and 1 ventrodistal transparent membrane-like process, and 2 ventral spiniform setae and 2 subdistal simple setae. Propodus broad, with inner spiniform seta, and 1 outer proximal, 3 dorsodistal, and 1 ventrodistal simple seta. Palm with 1 ventroproximal and 1 mid-ventral transparent membrane-like process, 2 ventral spiniform setae, and 2 ventro-subproximal and 3 ventro-subdistal simple setae. Dactylus with ventrodistal short spiniform seta and 1 mid-ventral, 5 subdistal, and 3 distal simple setae. Unguis naked, length nearly two-thirds dactylus length.

Pereopod 2 ( Fig. 3B View Figure 3 ) subchelate, as robust as pereopod 1. Basis with dorsal plumose sensory seta, and 2 dorsal and 2 ventral simple setae. Ischium with ventrodistal simple seta. Merus with dorsodistal spiniform seta, and 1 dorsodistal and 3 ventrodistal simple setae. Carpus triangular, with ventrodistal prolongation, 1 ventroproximal and 1 ventrodistal transparent membrane-like process, 1 mid-ventral and 1 ventrodistal spiniform seta, and 1 outer and 3 ventral simple setae. Propodus with dorsal plumose sensory seta and 2 subproximal, 2 dorsal, and 3 dorsodistal simple setae. Palm with 1 ventroproximal, 1 mid-ventral, and1 ventro-subdistal transparent membrane-like process, mid-ventral two-pronged spiniform seta, 1 ventro-subproximal and 1 ventro-subdistal spiniform seta, and 3 ventro-subdistal simple setae. Dactylus with 2 middle and 6 distal simple setae. Unguis naked, length nearly half dactylus length.

Pereopod 3 ( Fig. 3C View Figure 3 ) subchelate, similar to pereopod 2 except in number of simple setae.

Pereopod 4 ( Fig. 3D View Figure 3 ) with basis, ischium, merus similar to those of pereopod 3 but narrower and bearing different numbers of plumose sensory setae and simple setae. Carpus trapezoidal, with 4 small ventral processes, ventrodistal spiniform seta, dorsodistal plumose sensory seta, and 1 dorsodistal and 4 ventral simple setae. Propodus with dorsodistal plumose sensory seta and 2 dorsodistal simple setae. Palm with several small ventral processes, ventrodistal spiniform seta, and 1 inner and 4 ventrodistal simple setae. Dactylus narrow, with 1 ventro-subproximal, 1 dorso-subdistal, and 9 distal simple setae. Unguis naked, length nearly one-quarter dactylus length.

Pereopods 5–7 ( Fig. 3E–G View Figure 3 ) similar to pereopod 4, except for number of plumose sensory setae and simple setae.

Pleopod 1 ( Fig. 4A View Figure 4 ) protopod with 2 inner hooks and outer simple seta. Exopod not operculiform, length 1.82 times width, with 22 plumose setae (one broken). Endopod length 1.80 times width, 0.96 times exopod length,with 9 plumose setae. Protopod, exopod, and endopod partly covered with fine setae.

Pleopods 2–5 ( Fig. 4B–E View Figure 4 ) similar to pleopod 1, except for number of plumose setae on endopod (9, 8, 9, 8 plumose setae on endopods 2–5, respectively).

Uropodal endopod ( Fig. 4F View Figure 4 ) length 1.64 times width, with 3 distal plumose sensory setae and 34 simple setae. Exopod ( Fig. 4G View Figure 4 ) oval, widest at proximal third, length 1.47 times width, with 15 simple setae (2 with tip broken); inner margin smooth, without serration or crenulation; outer margin not concave.

Remarks. The uropodal exopod in female K. tamago sp. nov. is widest at the proximal third; the inner margin is smooth, without serration or crenulation; the outer margin is not concave. Females of K.tamago sp. nov. share these features with females of K. gidgee and K. indonesica , but differ from them as follows (character states in parentheses, K. gidgee and K. indonesica , respectively): uropodal exopod broader, with the length/width ratio 1.47 (2.1; 2.4); uropodal endopod broader, with the length/width ratio 1.64 (2.1; not mentioned); telson margins smooth (dentate distally; paired prominent dentations on distolateral margins) ( Poore and Lew Ton, 1988; Annisaqois and Wägele, 2021).

The description of the tailfan of female K.serritelson is insufficient, but K. tamago sp. nov. differs from this species in having a more-elongate antennular flagellum article 2 (length 2.50 times the width in K. tamago sp. nov.; 1.44 times in K. serritelson ), a more-elongate antennal peduncle article 5 (length 2.14 times the width in K. tamago sp. nov.; 1.56 times in K. serritelson ), and the carpus of pereopod 1 lacking the ventrodistal prolongation present in pereopods 2 and 3 (ventrodistal prolongation present on the carpus of pereopod 1 in K. serritelson ) ( Wägele, 1981).