Heterolaophonte curvata ( Douwe, 1929 )

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 : 517-530

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.5664053
persistent identifier	https://treatment.plazi.org/id/A62A87E3-4B20-FFDD-11B1-FE729E4FFB3D
treatment provided by	Plazi
scientific name	Heterolaophonte curvata ( Douwe, 1929 )
status

Treatment

Heterolaophonte curvata ( Douwe, 1929)

( Figs. 10 View FIGURE 10 –21)

Synonymy. Laophonte curvata, Douwe (1929) , p. 286, figs. 4–9.

Neotype designation. With the type materials lost, a neotype is designated here in order to clarify the taxonomic status of H. curvata . Neotype is a female, collected on 10.09.2002 from a beach in Yaroz Feneri Village (St. 11), Trabzon province, Turkey (41º05.677'N 39º23.718'E), dissected on 8 Slides (deposited in the NHMUK reg. no. 2014.7).

Material examined. St.11 (10.09.2002), one ♀ and one ♂, each dissected on eight slides (deposited in the NHMUK reg. no. 2014.8-9); St.2, one ♀ dissected on four slides, four ♀, one ♂, (01.05.2001); St.4, three ♀, two ♂ (13.09.2002); St.7, three ♀ (11.09.2002); St.8, six ♀ (1 ♀, dissected on 1 slide) and one ♂ (11.09.2002), St.12, one ♀ (dissected on 2 slides), three ♂ (10.09.2002); St. 13, two ♀ (09.09.2002); St. 14, three ♀, one ♂ (14.09.2002); St. 16, one ♂ (29.11.2007); St. 18, one ♀ (26.11.2007); St. 19, two ♀, one ♂ (08.04.2007), one ♀ (25.11.2007); St.20, two ♀ (24.11.2007); St. 21, one ♂ (24.11.2007); St. 22, one ♀ (24.11.2007). All other materials are 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. 10 View FIGURE 10 A, B). Total body length 686–706 µm (n = 20; mean = 694 µm). Shape, ornamentation and structure of body, rostrum and cephalothorax as in H. uncinata . Entire surface covered with tiny spinules (see insert on Fig. 10 View FIGURE 10 A). Rostrum triangular ( Fig. 12 View FIGURE 12 A), with 1 pair of welldeveloped sensilla near apex; midventral tube-pore in subapical position; with transverse incomplete surface ridge dorsally indicating original articulation; with ovoid patch of fine spinules located centrally. All prosomites without defined hyaline frills; posterior margins fringed with small spinules. Urosomites ( Fig. 11 View FIGURE 11 A) with several rows of spinules on ventral surface extending laterally ( Fig. 10 View FIGURE 10 B). Genital double-somite with transverse surface ridge dorsally and laterally ( Fig. 10 View FIGURE 10 A, B), 2 pairs of pores located medially; completely fused ventrally ( Fig. 11 View FIGURE 11 A). Copulatory pore located in proximal depression; gonophores fused medially forming single genital slit covered on either side by operculum derived from sixth leg; P6 with small protuberance bearing 1 bare seta ( Fig. 11 View FIGURE 11 A). Anal somite ( Fig. 11 View FIGURE 11 A, B); anal operculum flanked by 1 pair of sensilla; anal opening bordered by 1 frill bearing fine setular extensions. Caudal rami ( Fig. 11 View FIGURE 11 A, B). Divergent, cylindrical, about twice as long as wide; each ramus with 7 bare setae: seta I subventral, bare and shortest; setae II and III bare; setae IV and V fused basally, and with fracture planes; seta VII tri-articulate at base with spinular row near insertion. Each ramus covered with hardly visible spinules on dorsal surface; additional spinular ornamentation present around ventral and dorsal distal margins; long tube-pore present near ventral distal margin.

Antennule ( Fig. 12 View FIGURE 12 B) 7-segmented; segmentation, setation and ornamentation as in H. uncinata except for 1 plumose seta on segment 2. Antenna ( Fig. 17 View FIGURE 17 C); segmentation, setation and ornamentation as in H. uncinata except for allobasis with 1 transverse proximal spinular row near base of exopod. Mandible, maxillule, maxilla, maxilliped as in H. uncinata .

Swimming legs P2–P4 (Fig. 14B; 16A, B) with wide intercoxal sclerites bearing hardly visible spinules and with well developed praecoxae. Praecoxae with spinules along outer margin. Exopods 3-segmented, endopods 2- segmented.

P1 (Figs. 14A; 15A, B, C) with 2-segmented exopod. Ornamentation of intercoxal sclerite and praecoxae as in other swimming legs. Coxa large; with 3 spinular rows on anterior surface, inner and outer margins as figured. Basis with bipinnate seta near insertion of endopod; with spinular rows on anterior surface, along inner and outer margins; with bipinnate seta at outer margin. Exopodal segments with spinular rows as figured. Exp-2 (Figs. 14A; 15C) about twice as long as exp-1. Enp-1 about 5 times as long as width ( Fig. 15 View FIGURE 15 A), and about 3 times as long as exopod, with spinular row located medially on anterior surface; enp-2 with one strong, minutely denticulate claw, and 1 small naked seta (arrowed in Fig. 15 View FIGURE 15 B); several spinules along outer margin and around inner distal corner.

P2–P4 (Figs 14B; 16A, B). Coxae and bases with spinular rows along outer margin and on anterior surface; basis with tube-pore on anterior surface; outer margin of basis with bipinnate seta; exopodal and endopodal segments with elaborate spinular/setular ornamentation along outer margins as figured; outer half of endopod segments of P2-P3 covered with fine spinules. P3–P4 enp-1 shorter than enp-2, P3 enp-2 about as long as enp-1, P2-P4 enp-1 without seta; P2 and P4 enp-2 with tube pore located terminally on anterior surface. Spine and setal formulae of swimming legs as follows:

Fifth pair of legs ( Fig. 17 View FIGURE 17 B). Similar to that of H. uncinata . Exopod and baseoendopod each with pattern of spinules on anterior surface as figured. Baseoendopod with 3 tubepores on anterior surface; endopodal lobe extending to middle of exopod, with 2 apical and 3 medial bipinnate setae, outermost minutely pinnate seta shortest, 2 proximal setae minutely pinnate. Exopod with 6 setae (one of which naked).

Redescription of male (based on material from St.11). Body ( Figs. 17 View FIGURE 17 A; 18A) similar to H. uncinata . Body length 638–670 µm (n=10; mean 650 µm). Rostrum narrower than female ( Fig. 12 View FIGURE 12 C) with 1 pore (arrowed in Fig. 18 View FIGURE 18 B), surface with 1 group of spinules on anterior surface as figured. All urosomites with several spinular rows centrally, some rows extending laterally. Caudal rami as in female ( Figs. 11 View FIGURE 11 C, D; 18A, D).

Antennule ( Fig. 12 View FIGURE 12 C; 13A, B, C) 8-segmented; subchirocer with geniculation between segments 5 and 6. Segment 1 with spinules along anterior margin and covered with tiny spinules dorsally as figured. Segment 5 swollen with 1 robust spinulose seta swollen at base ( Fig. 12 View FIGURE 12 C; arrowed in Fig. 13 View FIGURE 13 A) with 1 long aesthetasc (arrowed in Fig. 13 View FIGURE 13 C) and 1 semispinulose seta. Segment 6 with 2 modified spinous element (arrowed in Fig. 13 View FIGURE 13 B). 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-[6], 4-[2], 5-[11 + 1 modified + (1 + ae)], 6-[2 modified spinous elements], 7-[1], 8-[7 + 1 modified + acrothek]. Apical acrothek consisting of 1 aesthetasc and 2 naked setae ( Fig. 12 View FIGURE 12 C). Surface ornamentation of intercoxal sclerites and protopods of P1–P4 ( Figs 16 View FIGURE 16 C; 19A, B) generally as in ♀. Many modifications on P1-P4.

P2 ( Fig. 19 View FIGURE 19 A). Exopod segments more robust than female. Exp-3 more sclerotised, outer spines stouter and naked, innermost spine remarkably shorter and stouter (homologous to terminal bipinnate spine of female). Enp-1 terminally elongated as 1 apophysis carrying 1 pore at tip and with 1 group of spinules along inner and outer margins. Enp-2 with longer spinules along outer margin, terminal seta longer and bipinnate, proximal inner seta transformed into 1 naked spine (arrowed in Fig. 19 View FIGURE 19 A; indicated with upper right arrows in Fig 20 View FIGURE 20 A).

P3 ( Fig. 19 View FIGURE 19 B). Exp-3 slightly curved and sclerotised, outer spines naked and robust (posterior fine spinular ornamentations only visible with SEM, arrowed in Fig. 20 View FIGURE 20 D), middle outer spine modified into 1 longer naked spine, outer terminal spine modified into 1 shorter naked spine. Enp-1 with long setules along inner margin. Enp-2 with long spinules along inner margin, outermost seta transformed into 1 apophysis (arrowed in Fig. 19 View FIGURE 19 B; indicated with lower left arrow in Fig. 20 View FIGURE 20 A), anterior surface with 2 stout spinules.

P4 ( Fig. 16 View FIGURE 16 C). Inner seta of exp-2 minutely pinnate and smaller than that of female. Terminal inner spine of female reduced to 1 small naked seta. Enp-1 with 2 small inner spinules. Enp-2 ornamented with long spinules along outer margin and 1 patch of anterior minute spinules near base of tube pore; with small pinnate inner seta; terminal seta semispinulose about twice longer than outer terminal seta.

Fifth pair of legs ( Fig. 11 View FIGURE 11 C). Baseoendopods fused medially ( Figs. 11 View FIGURE 11 C; 18C), with setophore bearing outer naked basal seta; endopodal and exopodal lobes vestigial bearing 2 and 4 small naked setae respectively; with spinules and 1 tube-pore near base of setophore (indicated with upper arrow in Fig. 20 View FIGURE 20 B). Sixth pair of legs ( Fig. 11 View FIGURE 11 C) symmetrical; represented by 1 plate fused to ventral wall of supporting somite ( Figs. 11 View FIGURE 11 C; 18C); outer distal corner produced into small process bearing several spinules at base and 2 naked setae (indicated with lower arrow in Fig. 20 View FIGURE 20 B).

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

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

Remarks. Heterolaophote curvata was originally described from Bay of Cavaliere and Cette along the Mediterranean French coast by Douwe (1929). The present specimens differ from the original description in the presence of four setae (instead of one) on antennary exopod and in having one small inner terminal seta on the third exopodal segment of the male P3. But, it is highly possible that these setae have been overlooked by Douwe (1929). Further comparisons about the spinular ornamentation on the appendages cannot be made since the original FIGURE 14. Heterolaophonte curvata , ♀. A, P1, anterior; B, P3, anterior.

figures lack sufficient detail. On the other hand our specimens match well with the previous descriptions ( Lang 1948; Apostolov 1990; Apostolov & Marinov 1988). But, the setation on the figures and the setal formulae given in the text by Apostolov & Marinov (1988) contain several discrepancies which might have resulted from typing errors. Therefore the population reported by Apostolov & Marinov (1988) from the Black Sea is accepted as conspecific with the present species presented herein.

The subspecies H. curvata micrarthros has an interesting history of description. This subspecies was originally created as a new variety of H. curvata from Yalta (Crimea) by Marcus & Por (1960). But, they determined that a previous report of H. curvata by Por (1960) from Romanian Black Sea coast (Eforie) was conspecific with the specimens from Yalta. Although Por (1960) noted some differences between Romanian specimens and the typical H. curvata he decided at that time that creating a new variety was not justified since he had only male specimens from a single locality. Later Marcus & Por (1960) found female specimens in Yalta (Crimea) and created H. curvata var. micrarthros and concluded that their specimens differed from typical H. curvata by the following five features: i) Exopod of the antenna more developed than as that described by Douwe (1929) and bearing 4-5 setae instead of one, ii) terminal exopod segment of P3 has an extra seta and the P3 enp-2 a very weak thumb-shaped spine, iii) anal operculum with spinules on free border, iv) inner modified spine of P2 enp-2 of the male is less chitinized and weaker, v) the P4 endopod of the male is 2-segmented instead of one. But, these diagnostic features of H. curvata micrarthros are also found in the present redescription of H. curvata . On the other hand, several new differences can now be defined between H. curvata micrarthros and presently redescribed H. curvata ; i) caudal rami shorter in female, ii) terminal exopodal segment of P4 with 5 setae/spines in male, iii) P4 enp-2 of male with one long seta, iv) structure and the ornamentation of setal elements of female P5 are different. On the other hand, it should be pointed out that the setal formula of P4 differs between female and male of H. curvata micrarthros , viz, terminal exopodal segment of P4 with 5 setae/spines in female but with 4 setae/spines in male and P4 enp-2 of male with one long seta in female but with 2 setae in male. This might mean that H. curvata micrarthros was described on the basis of male and female specimens belonging to different species. As mentioned above, the female specimens of H. curvata micrarthros were collected from Eforie ( Romania) but the male specimens were obtained from Yalta. The description of the male possibly belongs to a taxon closely related to H. curvata (Por, 1960) but the female specimens described from Yalta ( Marcus & Por 1960) may not even belong to the genus Heterolaophonte but another genus such as Paralaophonte . Therefore, the position of H. curvata micrarthros within the genus should provisionally be considered doubtful. The reports of H. curvata micrarthros given by Marinov (1971) and Apostolov & Marinov (1988) should also be confirmed.