Lourinia wellsi sp. nov.

(Figs. 6–11)

Synonym. Lourinia armata (Claus, 1866) sensu Alper et al. (2015); Karaytuğ & Koçak (2018).

Type locality. Turkey, Aydın province, intertidal zone of Dipburun Beach / Kuşadası (N37.6634167°, E27.0090556°); collected on 25 October 2012 .

Type material. Holotype ♀ dissected on nine slides. Allotype ♂ collected on 25 November 2012, dissected on nine slides. Paratypes represented by six ♀♀ and three copepodids. The holotype and allotype are deposited in the NHM, London.

Additional material examined. All additional samples mentioned below were obtained from washings of the macroalgae which were collected from the localities. One ♀ in washings of Posidonia oceanica, collected at 1 m depth from a beach located at northwest of Seddülbahir Village / Eceabat / Çanakkale (40.051212°, 26.167424°); collected on 05 July 1995 . Three ♀♀ from Tınaztepe cove/ Urla / İzmir / Turkey (N38.4013056°, E26.4882778°); collected on 24 May 2012 . Three ♀♀ and two ♂♂ from Çanak cove/ Foça / İzmir / Turkey (N38.6666111°, E26.7428333°); collected on 25 May 2012 . One ♂ from Bademli beach/ Dikili / İzmir / Turkey (N39.0388333°, E26.8253611°), collected on 25 May 2012 . Two ♀♀ from beach of Burcu holiday site/ Çeşme / İzmir / Turkey (N38.3472222°, E26.4505000°); collected on 16 June 2013 . One ♀ from Tınaztepe cove/ Urla / İzmir / Turkey (N38.4013056°, E26.4882778°), collected on 16 June 2013 . One ♂ from the sandy beach at İkiz Cove / Eceabat / Çanakkale / Turkey (N40.06317°, E26.17724°); collected on 28 September 2013 . One ♀ from a beach located at west of Sazlıdere / Keşan / Edirne / Turkey (N40.64288°, E26.72029°); collected on 29 September 2013 . One ♀ from beach of Kumlimanı holiday site/ Eceabat / Çanakkale / Turkey (N40.16248°, E26.24680°); collected on 29 September 2013 . One ♀ from Kanlısırt Beach / Eceabat / Çanakkale / Turkey (N40.16248°, E26.24680°); collected on 23 February 2014 .

Description of female. Body shape (Fig. 6A–B) similar to that of L. aff. armata . Total body length: 1,094 μm (mean = 962 μm; n = 21); maximum width: 212 μm (mean = 215 μm; n = 21). Rostrum triangular, defined at base with two sensillae with serrate tip (Fig. 6C). Dorsal surface of genital double-somite, third urosomite and anal somite ornamented with microspinules as figured. Spinular ornamentation of genital double-somite, third and fourth urosomites similar to L. aff. armata (Figs. 6B; 11A). Anal somite with one pair of sensilla dorsally; anal operculum straight, margin ornamented with short setules.

Antennule (Fig. 7A) 7-segmented. First segment ornamented with spinule rows as figured, with one seta. Second segment with nine setae. Third segment longest, with six setae. Fourth segment with one seta and with aesthetasc fused basally to seta arising from common pedestal. Fifth and sixth segments with one and two setae, respectively (Fig. 7B). Distal segment with six setae and with apical acrothek consisting of an aesthetasc and two setae. Setal formula of antennule: 1–[1]; 2–[9]; 3–[6]; 4–[1+ (1 + ae)]; 5–[1]; 6–[2]; 7–[6 + acrothek].

Antenna (Fig. 7C). Coxa rectangular, ornamented with spinule row as figured. Allobasis ornamented with spinule row as figured. Exopod 1-segmented, with two bipinnate setae apically. Endopod 1-segmented, ornamented with spinule rows as figured; protruding at outer corner apically; lateral armature consisting of two spines (distal one bipinnate), distal armature consisting of one long bipinnate spine and three naked spines (outer one fused basally to a small seta).

Mandible, maxillule, maxilla and maxilliped as in L. aff. armata .

P1 (Fig. 8A). Spinular ornamentation of praecoxa, coxa and basis similar to L. aff. armata . Inner spine of basis extending at most to end of first endopodal segment. Exopod 3-segmented, inner margin of second segment ornamented with setules; first and second segments without inner armature; distal segment with one inner, one apical seta and two outer spines. Endopod 2-segmented, shorter than exopod; first segment with one inner, distally pectinate seta; distal segment with two inner setae (proximal one distally pectinate) and one apical spine.

P2–P4 (Figs. 8B; 9A–D). Intercoxal sclerites, praecoxae, coxae and bases similar to L. aff. armata . Exopods 3-segmented, inner margin of second and third segments ornamented with setules; first segment without inner armature; second segment with one plumose (P2) (Fig. 8B) or one bare (P3) (Fig. 9A) or one long plumose (P4) (Fig. 9B) inner seta; distal segment with one plumose inner seta, two apical setae and three outer spines. Endopods 2-segmented, shorter than exopods; first segment with one distally pectinate (P2) (Fig. 8B) or one bipinnate (P3) (Fig. 9C) or one long, distally unipinnate (P4) (Fig. 9D) seta; second segment with three inner (two distally pectinate and one plumose), two apical setae (one naked and one plumose) and one outer spine (P2) (Fig. 8B) or three inner setae (two plumose, one distally pectinate), two plumose apical setae and one outer spine (P3) (Fig. 9C) or one distally pectinate inner seta; two plumose apical setae and one outer spine (P4) (Fig. 9D).

Fifth pair of legs (Figs. 7D; 11A) fused, baseoendopod well developed, outer basal seta naked. Endopodal lobe with six bipinnate elements; setae I–II spiniform, seta IV longest. Exopod distinct, ovoid, with five long bare setae.

Sixth pair of legs (Fig. 11B) covered by P5, with one spiniform outer element, one seta and three small, apically serrate, inner elements.

Caudal rami (Fig. 6D–F) about 1.6 times as long as broad, bearing six setae. Position of setae similar to L. aff. armata . Seta V naked. Spinules around ventral distal margin smaller than in L. aff. armata .

Description of male. Body (Fig. 10A) cylindrical, tapering posteriorly. Total body length about 712 μm (mean = 880 μm, n = 5). Maximum width: 152 μm (mean = 206 μm; n = 5). Ventral posterior margin of third and fourth urosomites with continuous row, fifth urosomite with paired rows of spinules, spinules regular in size (Fig. 11C). Sexual dimorphism in body size and spinular/microspinular ornamentation, antennule, P2–P3 endopods, and P5 and P6.

Antennule (Fig. 10B) 9-segmented, subchirocer. First segment ornamented with spinule rows as figured, with a bare seta at inner distal corner. Second segment with nine setae. Third and fourth segments small (Fig. 10C), with six and two setae, respectively. Fifth segment (Fig. 10D) with aesthetasc fused basally to seta on common elongate pedestal. Sixth segment (Fig. 10E) with seven elements (four naked setae and three pectinate setae with tube-like extension distally). Seventh segment naked. Eighth segment with one seta (Fig. 10E). Distal segment (Fig. 10F) with six setae and apical acrothek consisting of aesthetasc fused basally with two setae. Armature formula of antennule: 1–[1]; 2–[9]; 3–[6]; 4–[2]; 5–[1 + ae)]; 6–[7]; 7–[0]; 8–[1]; 9–[6 + acrothek].

P2 endopod (Fig. 8C). Proximal inner seta of enp-2 semiplumose along distal half and length slightly exceeding that of outer terminal spine. Inner apical seta of enp-2 about three times as long as length of outer terminal spine.

P3 endopod (Fig. 9E) 3-segmented. First segment with one bipinnate inner seta; second segment small, with one plumose inner seta and elongate apophysis forming harpoon-like tip. Length of apophysis about 4.2 times longer than distal segment. Distal segment longest, rectangular, with two plumose apical setae.

Setal formula of swimming legs:

Fifth pair of legs (Fig. 11C) fused; baseoendopod and exopod forming common plate; lobes not prominent. Exopodal lobe with one long bare seta medially, one unipinnate inner seta and four bipinnate setae; endopodal lobe with one long and two short bipinnate setae. Comparison of relative length of exopodal setae as follows: III>I>IV>II>V>VI.

Sixth pair of legs (Fig. 11D) asymmetrical; bearing three bare setae each, inner seta longest.

Etymology. The new species is named in honour of the late Prof. John Wells for his contribution to harpacticoid taxonomy.