Etymology. This species is named after the character of the video game Super Mario®, who, like our species, goes often underground and wears a funny mustache (mandibular palp). The epiteth is used as a noun in apposition.
Type locality. Samoylov Island, Lena river delta (72°22’22”N 126°28’47”E); wet moss; water temperature 3.9°C; conductivity 54 μS/cm; pH 7,22; September 10, 2019; coll. A. Novikov.
aterial examined. Holotype: female, dissected and mounted on 2 slides (ZM&G BP 541/1-a; 541/1-b). Allotype, male dissected and mounted on one slide (541/2). Paratypes: one female dissected and mounted on one slide (541/3), and two females and one copepodite V preserved in formalin (541/4).
Description. Female holotype. Body almost cylindrical, vermiform. Total body length of holotype from tip of rostrum to posterior margin of caudal rami: 0.419 mm. Cuticle very thin. Body colourless. Naupliar eye not discernible. Cephalothorax (Fig. 1) as wide as remaining somites. With cuticular window on cephalothorax dorsally, and on P2-bearing somite laterally. Rostrum small, fused to cephalothorax. Posterior margin of all somites smooth.
Cephalothorax with 27 pairs of sensilla and 4 pairs of pores. Second pedigerous somite with 5 pairs of sensilla, and one paired and one unpaired pore. Third pedigerous somite with 6 pairs of sensilla, and one unpaired pore. Fourth pedigerous somite with 5 pairs of sensilla, and single pore. Fifth pedigerous somite with 3 pairs of sensilla. Pedigerous somites 2-5 with rows of small spinules dorsally and laterally.
Genital-double somite (Figs. 2A, B) wider than long with dorsolateral rows of spinules; with 6 pairs of sensilla, and 1 pair of lateral pores, 1 pair of ventral double-pores and one unpaired dorsal pore. P6 strongly reduced to 1 pinnate seta. Genital field dense, with massive chitinous thickenings, and one pore and one short spinular row on each side; copulatory pore large; copulatory duct wide and short. Nodular thickening (arrow in Fig. 2B) round, closely spaced. Second abdominal somite with some dorsolateral transverse spinular rows as shown, with 3 pairs of sensilla, 1 pair of lateral pores, and 1 pair of ventral double-pores; with an interrupted, transverse, posterior spinular row latero-ventrally. Third abdominal somite with one lateral spinular row on each side, with 1 pair of lateral pores, and 3 pairs of ventral pores; with a continuous posterior spinular row latero-ventrally.
Anal somite (Fig. 2A, B) with 1 pair of sensilla, and 2 pair of pores dorsally; with spinular rows laterally and ventrally close to joint with caudal rami; anal operculum rounded, with 9 strong posterior spinules.
Caudal rami (Fig. 2A, B) small, length/width ratio 1.5, with 2 ventral pores; with spinules at base of setae I and II, and II, and with posterior spinules dorsally and ventrally; 7 setae as follows: apical setae IV and V long (0.025 and 0.036 mm) with spinules; seta VI parallel to seta V; seta VII triarticulated.
Antennule (Fig. 3A): short, 8-segmented. Segment 4 with large aesthetasc fused at base with long seta; aesthetasc on 4th segment larger tan aesthetasc on last segment. Segment 8 with acrothek consisting of slender aestetasc and two setae fused basally. Armature formula: 1-[1], 2-[8],3-[5],4- [1+(1+ae)],5-[1],6-[3],7-[2],8-[5+acr].
Antenna (Fig. 3B) with unornamented coxa. Allobasis with one proximal and one medial rows of spinules, with one abexopodal seta. Free endopodal segment with one proximal and one subdistal spinule rows on inner margin, with 2 lateral spines, and one medial and one subdistal outer frill; apically with 3 geniculate setae, 2 spines and 1 small seta; outermost geniculate spinulose seta fused basally to small slender seta. Exopod 2-segmented, elongate; first segment with pinnate seta, second segment with 3 naked setae.
Mandible (Fig. 4A). Coxa elongated, with few spinules. Gnathobase with 2 bicuspidate teeth, several multicuspidate teeth, and one pinnate dorsal seta. Palp reduced, 1-segmented, with single short seta.
Maxillule (Fig. 4B). Praecoxa with 2 rows of spinules. Praecoxal arthrite with 7 strong pectinate setae, and one pinnate ventral seta. Coxal endite with one pinnate filiform seta and one strong seta. Basis with 5 setae one of which stronger. Endopod and exopod incorporated into basis, each represented by 1 setae
Maxilla (Fig. 4C). Syncoxa with inner and outer spinules as shown, with 2 elongated endites each with 3 pinnate setae. Allobasis drawn out into strong claw with 2 setae. Endopod small 1-segmented, with 2 setae.
Maxilliped (Fig. 4D) subchelate, comprising syncoxa, basis and 1-segmented endopod. Syncoxa with one pinnate seta and with 2 groups of spinules. Basis elongated, with one row of large inner spinules, and 3 rows of outer spinules. Endopod with 1 small seta and strong spinulose claw.
P1 (Fig. 4E) with 2-segmented rami. Praecoxa with rows of spinules. Coxa with 1 proximal, 3 lateral and 4 distal rows of spinules. Intercoxal sclerite wide. Basis with one proximal pore, with rows of spinules as figured, with one inner and one outer spinulose spine. Exopodal and endopodal segments with outer spinules as shown. First exopodal segment with one outer spine; second segment with 3 outer spines and 2 long geniculate apical setae. Endopod short, reaching middle of third exopodal segment; first endopodal segment and first exopodal segment subequal in length, with one inner seta; second segment with one strong outer spine, one long geniculate seta, and one small inner seta.
P2 (Fig. 5A): Praecoxa with one row of spinules. Coxa with 5 rows of spinules as figured. Basis with rows of spinules at base of endopod and exopod and with row of small spinules medially. Exopod 3-segmented; exopodal segments with outer spinules; first and second segments with one outer spine, without inner armature; third segment with two outer spines, two apical elements, and one inner seta. Endopod 2-segmented, short, reaching tip of second exopodal segment; first segment unornamented, with 1 inner seta; second segment with 1 inner, 2 apical, and 1 outer spine.
P3 (Fig. 5B): Praecoxa with one row of spinules. Coxa with rows of spinules as figured. Basis with one pinnate seta and with rows of spinules at base of exopod and endopod. Exopod 3- segmented; first and second segments as in P2; third segment with 2 outer spines, 2 apical elements, and 2 inner setae. Endopod as in P2.
P4 (Fig. 5C): Praecoxa and coxa with one row of spinules. Intercoxal sclerite with concave distal margin. Basis as in P3. Exopod 3-segmented; all segments with rows of outer spinules; first segment with one outer spine, and without inner armature; second segment with outer spine and inner seta; third segment with 2 outer spines, 2 apical elements, and 1 inner seta. Endopod as in P2.
Armature of swimming legs as follows:
P5 (Fig. 8A) with left and right baseoendopods fused medially; baseoendopod reaching about midlength of exopodal segment, outer seta of basis pinnate, slender. Endopodal lobe with 4 pinnate setae and 2 tube pores. Exopod with 2 slender and 1 pinnate setae.
Male allotype. Total body length from tip of rostrum to posterior margin of caudal rami: 0.336 mm. Sexual dimorphism expressed in the antennule, P2–P6, genital segmentation and ornamentation. Sensilla and pores on cephalothorax and thoracic somites as in female.Abdominal somites (Fig. 6) 1–3 with rows of small spinules dorsally; first abdominal somite with P6, the latter a plate completely fused to somite with one bare seta; second abdominal somite with four pairs of sensilla, and with posterior spinular row; third abdominal somite ornamented as in previous somite except for three pairs of sensilla only; fourth abdominal somite with ventral row of spinules, and 1 pair of lateral pores. Anal somite as in female. Anal operculum with posterior row of 5 strong spines.
Caudal rami (Fig. 6) small, length/width ratio 1.25, without spinules dorsally, laterally with some spinules at base of setae I and II, ventrally with row of spinules at the base of setae IV and V. All setae as in female.
Antennule (Fig. 3C) 10-segmented, haplocer with geniculation between segments 7 and 8. Segment 5 with large aestetasc fused at base with long seta. Segment 7 with pronounced articular surface, with one filiform seta, one thick seta and with two modified laminar setae. Segment 8 with 3 similar laminar modified setae. Segment 10 with acrothek consisting of slender aestetasc and two setae. Armature formula: 1-[1],2-[8],3-[8],4-[2],5-[5+(1+ae)],6- [2],7-[2+2 modified],8-[3 modified],9-[1],10-[7+acr].
P2 (Fig. 7A): Praecoxa, coxa, basis and exopod, largely as in female, except for shape of segments and setae length. Ornamentation of coxa and basis as figured. Endopod 2- segmented; first segment with row of outer spinules, with small inner seta; second segment elongated, with notch on distal outer margin, with row of outer spinules, with 2 apical and one inner seta.
P3 (Fig. 7B) strongly modified. Ornamentation of praecoxa, coxa, basis, and exopod as in female. Third segment of exopod shortened, with pectinate short inner setae. Endopod short; first segment flat and wide, with small inner seta; second segment with inner apophysis reaching tip of exopod, with spear-shaped tip; distal segment with two rounded thickenings, with one pinnate, and one whip-like thick setae.
P4 (Fig. 7C) as in female except for third exopodal segment and with pectinate inner seta. Endopod small, 2-segmented; first segment without inner seta; second segment with only 3 setae.
P5 (Fig. 8B) small. Baseoendopod short, outer basal seta slender. Endopodal lobe with 2 tube pores, and 2 pinnate setae. Exopod with 1 inner pectinate, 2 pinnate apical, and 1 outer naked seta.
Variability. P5 and ornamentation of anal operculum variable. One of female paratypes with asymmetric P5, exopod of one side with 4 setae. Paratype females have anal operculum with 8-9 spinules.