Bryocamptus (Bryocamptus) putoranus, Novikov & Sharafutdinova & Chertoprud, 2023

Novikov, Aleksandr, Sharafutdinova, Dayana & Chertoprud, Elena, 2023, Two new species of Bryocamptus (Copepoda, Harpacticoida, Canthocamptidae) from the Russian Arctic and comparison with Bryocamptus minutus (Claus, 1863), ZooKeys 1138, pp. 89-141 : 89

Bryocamptus (Bryocamptus) putoranus sp. nov.

Figs 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27

Material.

Holotype: Russia • ♀ dissected on two slides; Russia, Putorana Plateau , large nameless lake in the upper flow of the Neral River; 68.901987°N, 94.170533°E; depth 0.5-1 m; 4 Aug. 2021; E. Chertoprud leg; BP 548/1-a, BP 548/1-b . Allotype: Russia • ♂ dissected on one slide; collection data as for holotype; BP 548/2 . Paratypes: Russia • ♀ dissected on two slides (BP 548/3-a, BP 548/3-b) and ♂ dissected on one slide (BP 548/4); Putorana Plateau, large nameless lake; 68.898348°N, 94.174442°E; depth 0.5-1 m; 4 Aug. 2021; E. Chertoprud leg.

Description.

Female (based on holotype and paratype). Body subcylindrical (Fig. 19A ). Total body length from anterior margin of rostrum to posterior margin of caudal rami: 527 µm (n = 1). Cephalothorax (Fig. 19B, C ; Appendix 1), wider than remaining somites, length 144 µm, largest width 112 µm. Naupliar eye not observed. Rostrum (Fig. 21A ) small, fused with cephalothorax, with rounded end, with one pair of sensillae and pore located distal to sensillae. Posterior margin of cephalothorax and all pedigerous somites smooth.

Cephalothorax (Fig. 19B, C ; Appendix 1) with dumbbell-shaped dorsal window, seven pairs of pores, seven pairs of sensillae of central group (group C), 13 pairs of sensillae of marginal group (group P) and 21 pairs of ungrouped sensillae (marked as L in Table 4 and in Appendix 1). Second pedigerous somite with lateral windows, dorsal unpaired pore, lateral pair of pores and eight pairs of sensillae. Third pedigerous somite with dorsal unpaired pore, lateral pair of pores and nine pairs of sensillae. Fourth pedigerous somite with dorsal unpaired pore, lateral pair of pores and eight pairs of sensillae. Fifth pedigerous somite with lateral pair of pores and four pairs of sensillae.

Abdomen (Fig. 20A-C ) consisting of genital-double somite, two free abdominal somites and anal somite with caudal rami. All somites except anal somite with wavy posterior margin, on surface with spinular rows. Genital-double somite consists of last thoracic somite and first abdominal somite; wider than long; anterior part with four pairs of sensillae, dorsal unpaired pore, lateral paired pores, ventro-lateral and lateral rows of spinules; posterior part with four pairs of sensillae, pairs of ventral and lateral pores and lateral rows of spinules.

P6 (Fig. 20C ) fused with somite with two pinnate setae. Genital field (Fig. 20C ) long, laterally with eight-pore sieves; copulatory pore displaced to posterior part of somite, copulatory duct chitinised with two additional tubes, extending proximally to pair of labyrinthic rounded ducts and one chitinised unpaired duct.

Second, third abdominal and anal somites as in B. minutus . Anal operculum semilunar, with seven long simple spinules. Caudal rami (Fig. 20A-D ). Length/width ratio 1.5, with three ventral pores; with rows of spinules on ventral and dorsal side at base of seta IV and rows spinules at base of setae II and III. Seta I small, located near seta II. Setae IV, V and VI displaced to ventral side of caudal ramus. Apical seta IV (Fig. 20D ) bipinnate, with massive bulbous base and "helle Stelle". Apical seta V long, bipinnate, with "helle Stelle". Seta VII triarticulated (Fig. 20B ).

Antennule (Fig. 20B ) similar to that of Bryocamptus minutus . Differences expressed in more elongated segments, especially 3rd and 4th segments; one of setae on segment 2 pinnate. Armature formula: 1-[1],2-[9],3-[5],4-[1+(1+ae)],5-[1],6-[3],7-[2],8-[5+acr].

Antenna (Fig. 21B ) similar to that of Bryocamptus minutus . Allobasis and free endopodal segment slightly shorter. Allobasis with proximal outer spinular row, basal seta pinnate; without spinular row at base of endopodal seta.

Labrum (Fig. 22A ) similar to that of Bryocamptus minutus , but without semicircular spinular row on inner side.

Mandible (Fig. 21D, E ). Coxa and gnathobase as in Bryocamptus minutus . The palp elongated, with three apical setae.

Paragnaths (Fig. 22B ) similar to that of Bryocamptus minutus , with only two groups of spinules on anterior side and without proximal spinular row.

Maxillule (Fig. 22C ) similar to that of Bryocamptus minutus . Coxal endite without spinules; basis with group of spinules.

Maxilla (Fig. 22D ) as in Bryocamptus minutus , only with slight differences in length and armature of setae.

Maxilliped (Fig. 23A ) similar to that of Bryocamptus minutus . Differences are only in shorter syncoxa and basis.

Cuticular process between maxillipeds and P1 (Fig. 23B, C ) extremely high, with long spinules, five spinules on each side. Spinules on posterior margin.

P1 (Fig. 23D ) almost like in Bryocamptus minutus . Basis with two inner groups of long spinules. First exopodal segment with inner spinules. First endopodal segment reaching end of second exopodal segment. Second endopodal segments with smooth inner side. Differences also noticeable in shorter exopodal and endopodal segments.

P2 (Fig. 24A ; Table 3 ). Praecoxa with row of spinules. Coxa with one lateral row of large spinules, two anterior rows of large spinules and four anterior rows of small spinules. Intercoxal sclerite naked. Basis with proximal pore, rows of spinules at base of endopod and exopod; with outer spine. All endopodal and exopodal segments with outer spinules. Exopod three-segmented; first exopodal segment with outer spinulose spine, apically with frill; second segment with outer spinulose spine, inner pectinate seta, inner slender spinules and apical frill; third segment with three outer spinulose spines, two apical setae and one inner pectinate seta. Endopod two-segmented; first segment with inner seta; second segment with distinct border between ancestral segments, outer spinulose spine, two apical pinnate setae and two inner pectinate setae.

P3 (Fig. 24B ; Table 3 ). Praecoxa with spinular row. Coxa with one lateral row of large spinules, two anterior rows of large spinules and four anterior rows of small spinules. Intercoxal sclerite without spinules. Basis with outer seta, proximal pore, and rows of spinules at base of endopod and exopod. Exopod three-segmented; first exopodal segment with outer spinulose spine, outer spinules, apically with frill; second segment with outer spinulose spine, outer spinules, inner pectinate seta, inner slender spinules and apical frill; third segment with three outer spinulose spines, two apical setae and two inner pectinate setae. Endopod two-segmented; first segment with inner seta; second segment with distinct border between ancestral segments, outer spinules, outer spinulose spine, two apical pinnate setae and three inner setae.

P4 (Fig. 24C ; Table 3 ). Praecoxa with spinular row. Coxa with one lateral row of large spinules, two anterior rows of large spinules and four anterior rows of small spinules. Basis with outer seta, proximal pore, rows of spinules at base of exopod. Exopod three-segmented; first exopodal segment with outer spinulose spine, outer spinules, apically with frill; second segment with outer spinulose spine, outer spinules, inner pectinate seta, inner slender spinules and apical frill; third segment with three outer spinulose spines, two apical setae and two inner pectinate setae. Endopod two-segmented; first segment with inner seta, second segment with outer spinule, outer spinulose spine, apical spiniform spinulose seta, apical pinnate seta and two inner pectinate setae.

P5 (Fig. 25A ) with separate right and left baseoendopods. Baseoendopod reaching ~ 1/2 of exopodal segment; with four pores, spinule at base of outer seta; outer seta of basis pinnate, long. Endopodal lobe with four long bipinnate setae and two short bipinnate setae V and VI; with small process that may be pore between setae III and IV. Exopod with inner spinule, inner strong pinnate seta, long apical pinnate seta, naked subapical seta and two pinnate outer setae.

Male. Sexual dimorphism expressed in the antennule, P2-P6, genital segmentation and ornamentation, shape of caudal rami. Cephalothorax and thoracic somites as in female. P6 (Fig. 26B ) two asymmetric flaps fused to the somite, with one naked and one pinnate setae. Differences from female in abdomen structure as follows (Fig. 26A, B ): first abdominal somite free; first to third abdominal somites with spinular row encircling somite ventrally and laterally; anal somite with ventral spinules; caudal rami with normal setae IV and V; anal operculum with eight simple spinules.

Antennule (Fig. 25C, D ) 10-segmented, haplocer with geniculation between segments 7 and 8. Segments 1, 3, 4, 5, 6, 9, and 10 similar to those of B. minutus , but differ in length. Segment 2 with small pore on anterior side. Segment 7 with articular plate, with one filiform seta, one small caudate seta and with two large modified laminar setae. Segment 8 with proximal long dentate plate and three modified laminar setae. Armature formula: 1-[1],2-[9],3-[8],4-[2],5-[6+(1+ae)],6-[2],7-[2+2 modified],8-[3 modified],9-[1],10-[7+acr].

P2 (Fig. 26C, D ) as in female, except endopod. Endopod two-segmented. First segment with outer spinule and inner seta. Second segment with notch on distal outer margin, outer spinules, two apical pinnate slender setae and two inner pectinate setae.

P3 (Fig. 27A-C ): praecoxa, coxa, intercoxal sclerite as in female. Basis as in female, but with inner process. Exopod as in female, but third segment with pore. Endopod three-segmented. First endopodal segment with strong seta. Second endopodal segment with posterior seta and long apophysis with double tip. Third segment with probably two small inner setae and two apical pinnate setae.

P4 (Fig. 27D, E ): praecoxa, coxa, intercoxal sclerite, basis, exopod as in female. Endopod two-segmented; first segment short, unarmed; second segment with outer spinule, spinulose spine, outer apical spiniform spinulose seta and inner apical bipinnate seta.

P5 (Fig. 27B ) right and left fused medially. Baseoendopod with three pairs of pores, outer spinule and outer long pinnate seta; endopodal lobe with two strong spinulose apical spines. Exopod with two outer spinulose setae, naked outer subapical seta, long apical spinulose seta, one inner spinulose seta and one inner pectinate seta with long setulles.

Variability.

Individuals with two outer spines on the third exopodal segment of P2 and P4 were found (Figs 26D , 27E ). One female was also found with both simple and bifid spinules on the anal operculum.

Etymology.

The species is named so because it was found on the Putorana Plateau.

Remarks.

The species as a whole is similar to B. hutchinsoni , including the structure of caudal rami; however, it differs well in two-segmented endopods P2 and P3. Another find of B. hutchinsoni ( Carter 1944) differs markedly in the structure of its caudal rami and is not similar to B. putoranus sp. nov.

Figures

Figure 19. Bryocamptus putoranus sp. nov., female A habitus, lateral B cephalothorax and thoracic somites, lateral C cephalothorax and thoracic somites, dorsal. Scale bars: 50 µm.

Figure 20. Bryocamptus putoranus sp. nov., female A abdomen, dorsal B abdomen, lateral C abdomen, ventral D caudal setae, dorsal. Scale bar: 50 µm.

Figure 21. Bryocamptus putoranus sp. nov., female A rostrum B antennule C antenna D mandible E scheme of teeth of mandibular gnathobase. Scale bars: 5 µm (A); 10 µm (B-E).

Figure 22. Bryocamptus putoranus sp. nov., female A labrum, posterior (black dots is bases of spinules) B paragnaths, anterior C maxillule D maxilla. Scale bars: 10 µm.

Figure 23. Bryocamptus putoranus sp. nov., female A maxilliped B cuticular process between maxillipeds and P 1, ventral C cuticular process between maxillipeds and P 1, lateral D P 1. Scale bars: 10 µm (A); 5 µm (B, C); 25 µm (D).

Figure 24. Bryocamptus putoranus sp. nov., female A P 2, anterior B P 3, anterior C P 4, anterior. Scale bar: 25 µm.

Figure 25. Bryocamptus putoranus sp. nov., female A P 5, anterior; male B P 5, anterior C antennule, anterior D antennule, dorsal. Scale bars: 25 µm (A); 10 µm (B-D).

Figure 26. Bryocamptus putoranus sp. nov., male A abdomen, dorsal B abdomen, ventral C P 2, anterior D P 2 Exp 3, variance Scale bars: 25 µm.

Figure 27. Bryocamptus putoranus sp. nov., male A P 3, anterior B P 3 endopod, anterior C P 3 endopod, inner view D P 4, anterior E P 4 Exp 3, variance. Scale bars: 25 µm (A, D, E); 10 µm (B, C).