Strepus elongatus

Cheng, Yu-Rong, Liu, Shang-Yin Vanson & Dai, Chang-Feng, 2016, A new family of poecilostomatoid copepods (Strepidae fam. nov.) associated with the sun coral, Tubastraea coccinea Lesson, 1829 in Taiwan, Zootaxa 4174 (1), pp. 346-354 : 348-350

publication ID	https://doi.org/ 10.11646/zootaxa.4174.1.21
publication LSID	lsid:zoobank.org:pub:58592E7C-2616-456B-B619-1CEA2EFDEF81
DOI	https://doi.org/10.5281/zenodo.6071898
persistent identifier	https://treatment.plazi.org/id/BB7D87B4-FFFF-9F3D-FF4A-FD3AFB7DF8E4
treatment provided by	Plazi
scientific name	Strepus elongatus
status

Treatment

Strepus elongatus gen. et sp. nov.

( Figs. 1–2 View FIGURE 1 View FIGURE 2 )

Type locality. Taiwan, north coast; off Yaliu (25°12.307’N, 121°41.380’E), northwest of Keelung; washings of Tubastraea coccinea Lesson, 1829 . GoogleMaps

Type material. A total of 31 copepods (9 ♀♀, 24 ♂♂) were obtained from four localities in Taiwanese waters . Holotype ♀ (from type locality; NTUIO-CONF 0001), allotype ♂ (from type locality; NTUIO-CONF 0002) and remaining paratypes (NTUIO-CONF 0003) were deposited in the Institute of Oceanography , National Taiwan University, Taipei , Taiwan.

Prevalence. 15% at Yaliu; 17.5% at Doufu–Cape; 5% at Tiaoshi; 0% at Wanlitong.

Mean intensity. 1.5 at Yaliu; 3.1 at Doufu–Cape; 1.0 at Tiaoshi; 0 at Wanlitong.

Mean abundance. 0.23 at Yaliu; 0.55 at Doufu–Cape; 0.05 at Tiaoshi; 0 at Wanlitong.

Description of female. Body ( Fig. 1 View FIGURE 1 A–B) elongate and cylindrical, measuring 2.74 (2.66–2.90) mm in total length and 0.80 (0.77–0.82) mm in greatest width, based on five specimens. Ratio of body length to greatest width 3.43:1. Segmentation of body distinct, but incomplete. Head ( Fig. 1 View FIGURE 1 A–B) very small, distinctly set off from trunk. Urosome ( Fig. 1 View FIGURE 1 C) 3-segmented, much shorter than prosome; genital and postgenital segments recurved upward in some specimens. Areas of attachment of egg sacs located dorso-laterally. Egg sac not observed. Caudal ramus ( Fig. 1 View FIGURE 1 D) elongate, covered with denticles; bearing two terminal setae. Surface of body unornamented ( Fig. 1 View FIGURE 1 A–B).

Rostral area ( Fig. 1 View FIGURE 1 E, G) distinctly protruded and covered with denticles. Antennule ( Fig. 1 View FIGURE 1 E, G) 4-segmented; armature: 0, 3, 2, and 5 setae; all setae naked. Antenna ( Fig. 1 View FIGURE 1 H) stronger and roughly, 3-segmented; basal and second segment unarmed and broad; distal segment with three small denticles.

Labrum ( Fig. 1 View FIGURE 1 E) elongate and swollen. Mandible ( Fig. 1 View FIGURE 1 E–F, I) slender, with pointed blade fringed with teeth on distal side. Maxillule ( Fig. 1 View FIGURE 1 E–F, J) a small lobe tipped with two long setae. Maxilla ( Figs. 1 View FIGURE 1 E–F, 2A) 2- segmented; proximal segment large and unarmed; distal segment small, with a distal process fringed with spinules on outer side. Maxilliped ( Fig. 2 View FIGURE 2 B) 2-segmented; first segment largest, with two spiniform inner setae; second segment tipped with two long setae and one denticle. Legs 1–5 absent.

Description of the male. Body ( Fig. 2 View FIGURE 2 C) generally as in female, but much more slender, with abdominal region arched upward. Length 2.20 (2.10–2.48) mm and greatest width 0.39 (0.37–0.41) mm, based on five specimens. Ratio of body length to greatest width 5.64:1. Caudal ramus elongate, shaped and armed as in female.

Antennule, antenna, mandible, maxillule, maxilla, and maxilliped like those of female, but one additional aesthetasc present on second segment of antennule (at point indicated by a dot in Fig. 1 View FIGURE 1 G).

Legs 1–2 ( Fig. 2 View FIGURE 2 D–E) a small unornamented free segment carrying two terminal setae. Legs 3–5 absent.

Etymology. The species name is derived from the Latin elongatus , meaning “elongate”, and alludes to the slender body of the new species.

Molecular analysis. A phylogenetic analysis using 18S rDNA sequence data was undertaken to determine the phylogenetic position of S. elongatus within the Copepoda, and to elucidate its phylogenetic relationships with the other families in the Poecilostomatoida ( Fig. 3 View FIGURE 3 ). After trimming several indels, the final alignment set with total length of 1,662 bp was used to generate a Maximium Likelihood tree. Strepus elongatus gen. et sp. nov. was identified as a member of the Poecilostomatoida and sister of a clade including Xarifia sp. ( Xarifiidae ), Critomolgus sp. and Doridicola agilis (Rhynchomolgidae) , Anchimolgus sp. 1 and Anchimolgus sp. 2 ( Anchimolgidae ) in the ML tree with strong bootstrap support (100). The average distance between these species, which represent five families, is 0.028, while the distance between S. elongatus and those species is 0.064 ( Table 1).