Heterolaophonte uncinata ( Czerniavski, 1868 )

Karaytuğ, Süphan, 2014, Systematics of the genus Heterolaophonte (Crustacea, Copepoda, Harpacticoida), with redescription of H. uncinata and H. curvata, Zootaxa 3780 (3), pp. 503-533 : 506-516

publication ID	https://doi.org/ 10.11646/zootaxa.3780.3.4
publication LSID	lsid:zoobank.org:pub:BF90D095-4452-4222-84CB-232416BF7AE0
DOI	https://doi.org/10.5281/zenodo.5664051
persistent identifier	https://treatment.plazi.org/id/A62A87E3-4B2D-FFC8-11B1-FD549FD5FE9A
treatment provided by	Plazi
scientific name	Heterolaophonte uncinata ( Czerniavski, 1868 )
status

Treatment

Heterolaophonte uncinata ( Czerniavski, 1868)

( Figs. 2–9 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 8 View FIGURE 9 )

Synonymy. Cleta uncinata Czerniavski, 1868 , p 42, plate I, Figures 19 View FIGURE 19 –29.

Neotype designation. With the type materials lost, a neotype is designated here in order to clarify the taxonomic status of H. uncinata . Neotype is a female, collected on 10.09.2002 from Tirebolu Beach (St. 9), Giresun province, Turkey (41º00.249'N 38º48.473'E), dissected on eight slides (deposited in the NHMUK reg. no. 2014.1).

Material examined. St.9, one ♀ dissected on two slides (deposited in the NHMUK reg. no. 2014.2), two ♀, (deposited in the NHMUK reg. no. 2014.3–4), one adult ♂ dissected on eight slides (deposited in the NHMUK reg. no. 2014.5), one ♂ (deposited in the NHMUK reg. no. 2014.6); St.1, two ♀ (16.09.2001), three ♀ (10.08.2002); St.5, two ♀ and two ♂ (09.07.2001), two ♀ (13.09.2002); St.6, two ♀, two ♂ (13.09.2002); St.7, one ♀ (11.09.2002); St.10, one ♀, two ♂ (10.09.2002); St.15, one ♀ (14.04.2007); St.17, five ♀ (27.11.2007); St.20, four ♀ (07.04.2007) deposited in the collection of Zoological Museum at the Biology Department of Mersin University. Undissected materials are whole mounted on slides.

Redescription of female (based on neotype). Body ( Fig. 2 View FIGURE 2 A, B). Total body length 518–656 µm (n = 10, mean = 563 µm). Largest width at posterior margin of cephalic shield. Urosome gradually tapering posteriorly. All somites covered with hardly visible minute spinules (as arrowed in Fig. 2 View FIGURE 2 A). Rostrum triangular ( Fig. 2 View FIGURE 2 A), with pair of sensilla near apex; midventral tube-pore in subapical position; completely defined at base. Cephalothorax with posterior margin fringed with small spinules; pleural areas well developed and rounded with lobate posterolateral angles; and pattern of sensillae as in Fig. 2 View FIGURE 2 A, B. All prosomites without defined hyaline frills; posterior margins fringed with small spinules. Urosome ( Fig. 2 View FIGURE 2 A, B) 5-segmented, comprising P5-bearing somite, genital double-somite and 3 free abdominal somites. Ventral surface of abdominal half of genital double-somite, second and third abdominal somites with rows of spinules ( Fig. 3 View FIGURE 3 A). Hyaline frills of urosomites not distinct. Genital double-somite with transverse surface ridge dorsally and laterally ( Fig. 2 View FIGURE 2 A, B), 2 pairs of pores located ventrally in the middle; completely fused ventrally ( Fig. 3 View FIGURE 3 A). Genital field ( Fig. 3 View FIGURE 3 A) with medium-sized copulatory pore located in median depression; gonopores fused medially forming single genital slit covered on either side by operculum derived from sixth leg; P6 with small protuberance bearing 2 bare setae. Anal somite with 2 pairs of ventral tube-pores ( Fig. 3 View FIGURE 3 A); anal operculum flanked by pair of sensilla; anal opening bordered by well-developed frill bearing long setular extensions ( Fig. 3 View FIGURE 3 B).

Caudal rami ( Fig. 3 View FIGURE 3 A, B) short, cylindrical, slightly longer than wide; each ramus with 7 bare setae: seta I inserted subventrally, bare and shortest; setae II and III bare; setae IV and V fused basally, and with fracture planes; seta VII tri-articulate at base; each ramus with small spinules on dorsal surface; additional spinular ornamentation present around ventral and dorsal distal margins; long tube-pore present near ventral distal margin.

Antennule ( Fig. 4 View FIGURE 4 A, B) seven-segmented; spinular ornamentation on segments 1–4 as figured. Segments 1–2 without spinous processes. Segment 4 with aesthetasc fused basally to seta and arising from distinct pedestal. Armature formula: 1-[1], 2-[8], 3-[7], 4-[1 + (1 + ae)], 5-[1], 6-[2], 7-[7 + acrothek]. Apical acrothek consisting of small aesthetasc fused basally to 2 naked setae.

FIGURE 6. Heterolaophonte uncinata , ♀. A, P1, anterior; B, P4, anterior.

FIGURE 7. Heterolaophonte uncinata , ♀. A, P2, anterior; B, P3, anterior.

Antenna ( Fig. 5 View FIGURE 5 A). Three-segmented, comprising coxa, allobasis and free 1-segmented endopod. Coxa small, with row of small spinules. Allobasis not elongate; without distinct surface suture marking original segmentation; with 1 abexopodal bipinnate seta near middle, with patch of fine spinules proximally near base of exopod. Exopod very small, with 4 naked small setae (2 apically and 2 subapically); 1 row of coarse spinules on posterior surface. Endopod about as long as allobasis; lateral armature inserted in distal half, consisting of 1 seta flanked by 2 strong spines; apical armature consisting of 2 strong spines and 3 geniculate setae (one geniculate seta fused basally to a short seta). Endopod with 1 row of long spinules in proximal half and row of spinules subapically.

Labrum well developed; spinular ornamentation on anterior surface as in Figure 2 View FIGURE 2 C. Mandible ( Fig. 2 View FIGURE 2 D) with well developed gnathobase bearing several multicuspidate teeth on distal margin as figured and 1 unipinnate seta at dorsal corner; palp elongate bearing 4 naked and 1 apical plumose seta, with spinules near base.

Maxillule ( Fig. 5 View FIGURE 5 C, D); praecoxa with several spinules around outer margin; arthrite strongly developed, with 1 naked seta on dorsal surface and 8 spines/setae around distal margin; 1 transverse row of long spinules on posterior surface. Coxa with cylindrical endite bearing 1 naked seta and 1 curved pinnate spine; with 1 spinular row on outer margin. Basis with cylindrical endite bearing 1 naked, 1 plumose setae and 1 pinnate spine. Endopod completely incorporated into basis, forming cluster of 2 tube-like and 1 naked setae; exopod 1-segmented but fused to basis, with 1 tube-like and 1 naked setae.

Maxilla ( Fig. 4 View FIGURE 4 D). Syncoxa with 3 endites; with several rows of spinules on posterior surface as figured; praecoxal endite small and cylindrical, with 1 plumose seta; both coxal endites with 2 pinnate setae and 1 naked seta; proximal coxal endite with 1 row of spinules posteriorly. Allobasis drawn out into 1 strong, slightly curved, distally pinnate claw; accessory armature consisting of 2 setae. Endopod represented by 3 naked setae, surrounded by spinules near base.

Maxilliped ( Fig. 4 View FIGURE 4 C). Syncoxa elongate, with 2 plumose setae and 3 rows of spinules. Basis with row of strong spinules along palmar margin next to patch of fine spinules. Endopod drawn out into 1 long distally pinnate claw; with 1 short accessory seta anteriorly.

Swimming legs. P1–P4 (Figs. 6A, B; 7A, B), with wide naked intercoxal sclerites and triangle praecoxae. Praecoxae with spinules along outer margin. Exopods 3-segmented, endopods 2-segmented.

P1 (Fig. 6A). Coxa large; with 2 spinular rows on anterior surface and 1 spinular row along outer margin. Basis with strong unipinnate seta near insertion of endopod, long spinules along inner margin, 1 spinular row on anterior surface and 1 bipinnate spine and 1 spinular row along outer margin. Exopodal segments with spinules along outer margins. Exp-1 with 1 bipinnate spine; exp-2 with 1 naked outer spine; exp-3 with 2 naked outer spines and 2 geniculate apical setae. Enp-1 about 4.5 times as long as wide, and about twice as long as exopod, with long spinules along proximal half of inner margin, and with spinules along outer margin; enp-2 with 1 strong, minutely denticulate claw, and 1 small naked seta; several spinules along outer margin and around inner distal corner. P2–P4 (Figs 6B; 7A, B). Coxae and bases with spinular rows along outer margin, on anterior and posterior surfaces; basis with tube-pore on anterior surface (P2,P3); exopods with 3 segments, exopodal segments with similar width/length ratio; outer margin of basis with naked seta; exopodal and endopodal segments with elaborate spinular/setular ornamentation as figured. P2–P4 enp-1 shorter than enp-2 (P2 enp-1 as long as enp-2) and without seta; enp-2 with tube pore. Spine and setal formulae of swimming legs as follows:

Fifth pair of legs ( Fig. 5 View FIGURE 5 B). Baseoendopods not fused medially. Exopod and baseoendopod discrete, each with pattern of spinules on anterior surface as figured. Baseoendopod forming, outer setophore bearing basal naked seta; with 2 tube pores on anterior surface; endopodal lobe extending middle of exopod, with 2 apical and 3 medial bipinnate setae, two proximal setae with small pinnules. Exopod with 2 plumose terminal setae, 2 naked terminal setae and 2 subapical outer naked setae.

Redescription of male (based on material from St.9). Body ( Fig. 8 View FIGURE 8 A). 495–574 µm (n = 5; mean 524 µm). Largest width at posterior margin of cephalic shield. Urosome narrower than prosome. Prosome ( Fig. 8 View FIGURE 8 A) 4- segmented, comprising cephalothorax and 3 free pedigerous somites. Free pedigerous somites with spinulate posterior margin; whole surface covered with tiny spinules as in ♀. Rostrum, antenna, mouth parts and P1 as in female. Urosome 6-segmented ( Fig. 8 View FIGURE 8 A), comprising P5-bearing somite, genital somite and 4 abdominal somites, ornamented with spinular rows ventrally as figured. All urosomites with surface ornamentation consisting of tiny spinules dorsally and laterally.

Antennule ( Fig. 8 View FIGURE 8 B, C). Eight-segmented, subchirocer. Segment 1 covered with groups of spinules along anterior margin as figured. Segment 5 swollen ( Fig. 8 View FIGURE 8 B, C). Segmental homologies: 1-(I), 2-(II–VIII), 3-(IX–XII), 4-(XIII), 5-(XIV–XX), 6-(XXI–XXII), 7-(XXIII), 8-(XXIV–XXVIII). Armature formula: 1-[1], 2-[9], 3-[5], 4-[2], 5-[8 + 5 modified + (1 + ae)], 6-[1 + 2 modified spinous elements], 7-[1], 8-[7 + acrothek]. Apical acrothek consisting of aesthetasc and 2 naked setae.

Swimming legs P2–P4 ( Fig. 9 View FIGURE 9 A, B, C) with 2-segmented endopods and 3-segmented exopods. Surface ornamentation of intercoxal sclerites and protopods generally as in ♀. Many modifications on P2-P4 exopodal and endopodal segments. P2-P3 ( Fig. 9 View FIGURE 9 A, B). All exopod segments more robust; inner setae and outer spines naked. Exp-3 curved and sclerotised, outer spines naked and robust, outer terminal seta modified into 1 naked spine, inner terminal setae reduced as 2 smaller naked setae.

P2 ( Fig. 9 View FIGURE 9 A). Enp-1 elongated with long spinules along inner and outer margins, enp-2 with long spinules along outer margin, innermost seta transformed into 1 naked spine (arrowed in Fig. 9 View FIGURE 9 A).

P3 ( Fig. 9 View FIGURE 9 B). Enp-1 with long spinules along inner and outer margins. Enp-2 with long fine spinules along inner margin; with very stout spinular row near outer margin; with 3 tube-pores on anterior surface. Enp-2 produced distally into short, spiniform outer apophysis (homologous with outer spine of enp- 2 in ♀, arrowed in Fig. 9 View FIGURE 9 B); innermost seta lost.

P4 ( Fig. 9 View FIGURE 9 C). Enp-1 with 2 spinules on inner and outer distal margins. Enp-2 with spinules on inner and outer margins; inner seta reduced to 1 small spine (arrowed in Fig. 9 View FIGURE 9 C).

Fifth pair of legs ( Fig. 3 View FIGURE 3 C). Baseoendopods fused medially, with setophore bearing outer naked basal seta and with 5 setae; with 2 pair of tube-pores.

Sixth pair of legs ( Fig. 3 View FIGURE 3 C). Symmetrical; represented by 1 plate fused to ventral wall of supporting somite; outer distal corner produced into small process bearing several spinules at base, 1 bipinnate inner and 1 naked outer seta.

Variability. No significant variation was observed among the examined specimens.

Distribution. Based on the examined materials, it can be assumed that H. uncinata has a wide distribution both in the Black Sea and the Mediterranean Sea.

Remarks. Heterolaophonte uncinata was originally described as Cleta uncinata from Cape St. John in the Black Sea. Cape St. John (now more often called "Cape Monastery"), located in Yalta, in the Crimea peninsula ( Czerniavski 1868) and it has been reported from few localities since then ( Lang 1948; Bodin 1997). Heterolaophonte uncinata is one of the species of the genus Heterolaophonte which requires urgent redescription. Unfortunately the type material is lost (personal communication with Prof. Dr. Rony Huys) and therefore a neotype is designated here to help in solving the taxonomic problem surrounding H. uncinata . Unfortunately figures of the original description lack sufficient detail to make meaningful comparisons with the present redescription. On the other hand, the old figures prepared by Czerniavski (1868) can still provide us many surprising details which are overlooked even in some recent publications. For example, the structure of the modified inner spine on P2 enp-2 of the male was well documented and figured. We believe that structure of this modified spine is a diagnostic feature for H. uncinata (arrowed in Figure 9 View FIGURE 9 A) and provides strong support that the redescribed specimens are conspecific with Czerniavski’s specimens.

There is some significant degree of variation among some previous reports ( Petkovski 1954; Marcus & Por 1960; Apostolov & Marinov 1988). Petkovski (1954) recorded H. uncinata from the Adriatic, but this species cannot be attributed to Heterolaophonte as it has very unusual characteristics. For example, P4 exp-2 has an abnormal process terminally carrying a plumose seta on the second exopodal segment; this is not found in any harpacticoid species. Apostolov & Marinov (1988) provided a supplementary description of H. uncinata from the Black Sea. According to Apostolov & Marinov (1988) the first seta on the plate of male P5 exopod is longer than the second seta, and the third seta is given as very long. In the present description of H. uncinata the first outer seta is shorter than the second seta, and the third seta is shorter than the second. The first inner lateral seta of P5 endopod lobe is given as naked but it is pinnate in the present specimen. The unipinnate spine of P1 basis was possibly overlooked by Apostolov & Marinov (1988). Another report of H. uncinata from the Black Sea (Yalta, Crimea) was provided by Marcus & Por (1960). But this report almost certainly represents a different species since it has 5 setae/spines on P2-P4 exp-3 of the female instead of 6 setae/spines in the present redescription, and also has 5 setae/spines on P2-P3 exp-3 and 4–5 setae/spines on P4 exp-3 of the male. In conclusion, the variation among previous H. uncinata reports ( Petkovski 1954; Marcus & Por 1960; Apostolov & Marinov 1988) is noteworthy. It can be speculated that H. uncinata may well be a species complex in which each population can only be separated from each other by the detailed comparisons.