Nitocra loweae, Yıldız & Karaytuğ, 2024

Yildiz, Nuran Oezlem & Karaytug, Suephan, 2024, Taxonomic revision of the Nitocra affinis Gurney, 1927 species complex (Harpacticoida, Ameiridae) with descriptions of four new species and re-evaluation of its subspecies, ZooKeys 1191, pp. 35-74 : 35

publication ID	https://dx.doi.org/10.3897/zookeys.1191.115545
publication LSID	lsid:zoobank.org:pub:CA90F8CA-E399-4605-873C-B538C376A168
persistent identifier	https://treatment.plazi.org/id/4DA4374E-752C-4EFC-8891-C0B25C11256C
taxon LSID	lsid:zoobank.org:act:4DA4374E-752C-4EFC-8891-C0B25C11256C
treatment provided by	ZooKeys by Pensoft
scientific name	Nitocra loweae
status	sp. nov.

Treatment

Nitocra loweae sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8

Type material.

Holotype: England • 1 ♀ (dissected on 7 slides) (NHMUK reg. no. 2023.0000); paratype: 1 ♂ (ethanol-preserved) (NHMUK reg. no. 2023.0000); additional paratypes; 2 ♀♀ (ethanol-preserved) (NHMUK reg. no. 2023.0000-0000). Brighton, 50°48.46'N, 00°04.85'W; washings of Polysiphonia fucoides algae collected at 1.5 m depth. Leg. David Ventham, 13.10.1993 (material originally registered as N. affinis under NHMUK reg. no. 2015.1108) (see Ventham 2011).

Description

(adult female holotype). Body semi-cylindrical (Fig. 3A, B View Figure 3 ), total body length measured from the tip of the rostrum to posterior end of the caudal rami 560-571 μm (average = 564.6, n = 3; holotype length = 571 μm). Sensilla and pore ornamentation as figured (Fig. 3A, B View Figure 3 ). Prosome composed of cephalothorax with completely fused first pedigerous somite, and three free pedigerous somites with smooth hyaline frills. Urosome five-segmented, comprising fifth pedigerous somite, genital double-somite and three free abdominal somites. Fifth pedigerous somite wider than other urosomites, with six sensilla and a lateral spinule row slightly extending dorsally. Genital double-somite (Figs 3A, B View Figure 3 , 4B View Figure 4 ) squarish, internal suture line (remnant of segmental fusion) strongly sclerotised, visible dorsolaterally at midlength of somite, ornamented with spinules as figured. Second and third abdominal somites with sensilla and spinules as figured (Figs 3A, B View Figure 3 , 4B View Figure 4 ). Genital field positioned near anterior margin of genital double-somite (Fig. 4B View Figure 4 ); paired gonopores opening via common midventral slit covered by genital operculum derived from fused vestigial sixth legs. P6 with one plumose seta and one naked seta (Fig. 4B View Figure 4 ). Copulatory pore large (Fig. 4B View Figure 4 ), leading via chitinised copulatory duct with supporting chitinised rod. Anal somite (Figs 3A, C View Figure 3 ; 4B View Figure 4 ) with a lateral row of spinules medially; ventrally with medial row of spinules (Fig. 4B View Figure 4 ); anal operculum apically with row of twelve robust spinules (Fig. 3C View Figure 3 ). Caudal rami (Fig. 3C View Figure 3 ) with robust spinules near inner margin running dorso-ventrally, and a middorsal pore; with a posterior row of strong spinules ventrally; with seven setae (Fig. 3C View Figure 3 ): seta I minute; seta II slightly displaced dorsally; setae IV and V well-developed and pinnate (Fig, 3D); seta VI located near inner distal margin and naked; seta VII proximally tri-articulate.

Antennule (Fig. 5A View Figure 5 ) eight-segmented. Setal formula 1-[1, plumose], 2-[7 +2 plumose], 3-[7 +1 plumose], 4-[3 +1 ae], 5-[2], 6-[3], 7-[4], 8-[5 +acrothek)]. Maximum length/maximum width ratio of antennular segments 1:1:1.4:1.2:1.2:2:1.5:2.8.

Rostrum (Fig. 5A View Figure 5 ) small, triangular, without clear demarcation between the distal and the proximal part of rostrum (cf. Fig. 1C View Figure 1 of N. affinis ) with tube pore distally and with two dorsal sensilla (Fig. 5A View Figure 5 ).

Antenna (Fig. 5B View Figure 5 ) comprising coxa, allobasis, one-segmented endopod and one-segmented exopod.. Coxa very short and unornamented. Allobasis cylindrical, ~ 2.7 × as long as maximum width, ornamented proximally with three spinule rows. Free endopodal segment with proximal part narrower than distal part, ~ 2.5 × as long as its maximum width, ornamented with surface frill subdistally, and with longitudinal row of spinules along inner margin, with another spinule row near the base of two lateral unipinnate spines flanking thin naked seta; apical armature consisting of five geniculate setae, one of them fused basally to additional unipinnate non-geniculate seta. Exopod with narrow proximal half and somewhat wider distal part, ~ 2.5 × as long as its maximum width, unornamented, armed with two curved, strong unipinnate apical setae and one spinulose subdistal seta, the latter longest.

Mandible (Fig. 5C View Figure 5 ). Coxal gnathobase with coarse teeth ventrally and with one unipinnate seta dorsally. Palp uniramous, two-segmented, comprising basis and one-segmented endopod. Basis with lateral spinule row midway and one curved robust unipinnate apical spine. Endopod with one short plumose lateral seta, five naked apical setae (three of them basally fused).

Maxillule (Fig. 5D View Figure 5 ). Praecoxa large with few spinules. Praecoxal arthrite rectangular; with two setae on anterior surface, lateral spinule row and distal armature consisting of four spines (two of which with apical combs) and one unipinnate seta. Coxal endite shorter than praecoxal arthrite, with long distally curved spine and three slender naked setae. Basis rectangular, with five slender naked setae on distal margin. Endopod represented by minute but distinct segment, unornamented and armed with two plumose apical setae. Exopod absent.

Maxilla (Fig. 5E View Figure 5 ). Syncoxa with spinule row and two well-developed (coxal) endites; proximal endite somewhat bulbous, expanded distally and armed with two plumose setae; distal endite cylindrical with two naked apical setae of equal in length. Allobasis transformed into claw-like pinnate endite; with a pinnate seta at base and with few spinules along convex margin near the base of endopod. Endopod represented by two slender naked setae equal in length.

Maxilliped (Fig. 5F View Figure 5 ) subchelate. Syncoxa with one plumose subapical seta and with spinule rows on posterior surface. Basis ~ 2.6 × as long as maximum width with row of spinules along inner margin and with row of spinules on outer distal corner. Endopod represented by strong claw accompanied at base by minute naked seta.

P1-P4 (Fig. 6A, C, D, F View Figure 6 ) exopod and endopod three-segmented. Intercoxal sclerite squarish and unornamented. Praecoxa triangular, outer margin with row of spinules. Exp-1 without inner seta. P1, P2 and P4 exp-2 with few, P3 exp-2 without few spinules along inner margin.

P1 (Fig. 6A View Figure 6 ). Coxa with anterior row of spinules as figured and few spinules along inner margin. Basis with fine setules along inner margin, and with spinule row near the base of short pinnate inner spine located at the base of endopod. Outer basal bipinnate spine located close to the exopod, overlaid by a row of strong spinules. Exp-1 smallest segment, carrying row of strong spinules on outer margin and subapically one bipinnate outer spine. Exp-2 also with an outer row of strong spinules, a bipinnate outer spine, and a long plumose seta on inner margin. Exp-3 with fine setules near inner distal margin, with one geniculate semi-plumose apical seta, one geniculate naked distal seta and three pinnate outer spines. Enp-1 longer than exopod, ~ 3 × as long as maximum width, and ~ 2 × as long as enp-1, 2 combined; inner margin with long longitudinal spinules; distal margin with four robust spinules, and a long plumose seta on inner subdistal margin; enp-2, 3 squarish and equal in length; enp-2 with a long, plumose seta on inner margin, and with two spinules on outer distal margin; enp-3 with one plumose inner seta, one apical unipinnate distal geniculate seta, and one apical unipinnate outer seta, outer margin with a row of spinules.

P2-P4 (Fig. 6C, D, F View Figure 6 ). Coxa with row of posterior spinules near outer margin and with an anterior pore near inner distal corner. Basis triangular, ornamented with spinule row along distal margin between the base of exopod and endopod, with anterior spinules on outer corner near the base of outer seta/spine. Exp-1, 2 with anterior spinules near the base of outer spine extending to the outer margin of the segment. Exp-1, 2 and enp-1, 2 with hyaline frills along inner distal margin. All endopodal segments covered with robust spinules along outer margin. Exp-2, 3 and enp-2 with a pore on anterior surface. P2-P4 exp-2 with one plumose seta; P2, P3 exp-3 with seven, P4 exp-3 with eight elements.

P5 (Fig. 4D View Figure 4 ). Baseoendopod with five spinulose setae (slightly fringed at tip) along distal margin and with setules along inner margin, with two anterior pores (one near the base of outer basal seta and the other one near the distal margin; outer basal seta plumose. Exopod with one anterior pore distally, with setules along inner margin and with robust spinules along distal margin, with six setae (setae I-VI, numbered from inner to outer margin respectively), setae I, IV, and V pinnate; setae II, III, and VI naked; seta II is the longest; outer margin of exopodal lobe with one tube pore, and with double spinules group.

Armature formula of the swimming legs:

Male. Body sensilla and surface pores as figured (Fig. 7A, B View Figure 7 ). Anal operculum with sensilla and spinules as figured (Fig. 7C View Figure 7 ). Sexual dimorphism in antennule (Fig. 8A-C View Figure 8 ), inner spine of P1 basis (Fig. 6B View Figure 6 ), inner distal seta of P3 exp-3 (Fig. 6E View Figure 6 ), P5 (Fig. 4C, D View Figure 4 ), and P6 (Fig. 4A View Figure 4 ). The innermost seta of P5 is abnormal in paratype (Fig. 4E View Figure 4 ).

Antennule (Fig. 8A-C View Figure 8 ), ten-segmented, setal formula; 1- [1, plumose], 2- [1 plumose+ 1 unipinnate+ 8], 3-[7], 4-[2], 5-[19 setiform elements+ 4 multipinnate spine+3+1+ae], 6- [2], 7- [3], 8-[2], 9-[5], 10- [5 +acrothek)].

Inner spine of basis of P1 hook-like (Fig. 6B View Figure 6 ).

Inner distal seta of P3 exp-3 (Fig. 6E View Figure 6 ) slender and shorter than in female.

P5 (Fig. 4C View Figure 4 ) baseoendopod armed with five spinulose setae (four of them equal in length, the second inner seta longest and 1.5 × as long as the other setae) and with two pores on anterior surface; exopod with six setae (outer margin with one naked seta (seta VI) and one spinulose seta (seta V), apical margin with one naked (seta IV) and two spinulose setae (setae II and III), inner margin with one long plumose seta (seta I) (abnormal seta of one leg arrowed in Fig. 4C View Figure 4 ; the same seta of the other leg normal), with four strong spinules along outer proximal margin and with two or three spinules along inner proximal margin.

P6 (Fig. 4A View Figure 4 ) asymmetrical, only one leg functional; each leg with two naked outer setae and short inner plumose robust seta.

Etymology.

The specific name is given in honour of Dr Miranda Lowe for her contribution to copepod taxonomy as a curator of the Crustacea collection of The Natural History Museum of London. It is a noun in the genitive case.