Farranula gibbula ( Giesbrecht, 1891 )

Wi, Jin Hee & Soh, Ho Young, 2013, Two Farranula (Copepoda: Cyclopoida: Corycaeidae) species from Korean waters, Journal of Natural History 47 (5 - 12), pp. 289-312 : 302-306

publication ID	https://doi.org/ 10.1080/00222933.2012.708454
persistent identifier	https://treatment.plazi.org/id/CC1B0862-2A4A-8C03-FE41-FE5BFCADFB4D
treatment provided by	Felipe
scientific name	Farranula gibbula ( Giesbrecht, 1891 )
status

Treatment

Farranula gibbula ( Giesbrecht, 1891)

( Figures 7–11 View Figure 7 View Figure 8 View Figure 10 View Figure 11 )

Corycaeus gibbulus Giesbrecht, 1891, p. 481 ; Giesbrecht 1893 [“1892”], p. 675, pl. 51, figures 22, 23; Mori 1937 (1964), p. 137, pl. 76, figs 12–16, pl. 77, figs 1–4.

Corycaeus pellucidus: Wolfenden 1906, p.1027 , figs F.

Corycaeus brevis: Farran 1911, p. 285 , pl. 10, figs 16, pl. 11, fig. 7.

Corycaeus (Corycaella) gibbulus: M. Dahl 1912, p. 115 , pl. 15, figs 14, 9, 10, 25, 35, 36; Tanaka 1957, p. 96, pl. 10, figs 611; 1960, p. 89, 90, pl. 38, fig. 12; Chen al. 1974, p.65, figures F,M; Zheng et al. 1982, p.148, fig. F

Farranula gibbula: Motoda 1963, p. 252 –255, fig. 27.

Material examined

In all, 109 ♀♀ and 55 ♂♂ collected from the East China Sea (to the west of Jeju island of Korea) (32 ◦ 00 ′ N, 126 ◦ 5 ′ E) on 17 June 2009, of which 5 ♀♀ and 5 ♂♂ were dissected and examined in detail and 2 ♀♀ and 2 ♂♂ are deposited in the National Institute of Biological Resources ( NIBR), Incheon, Korea ( NIBRIV0000245152 ) GoogleMaps .

Description of female

Body cylindrical, tapering posteriorly. Total body length in lateral view 1025 µm (average: 1012 µm, n = 4 individuals), measured from anterior margin of prosome to posterior margin of caudal rami. Urosome distinctly narrower than prosome ( Figure 7A,B View Figure 7 ).

Prosome length about 2.4 times longer than urosome including caudal rami, 3.6 times urosome length, excluding caudal rami. Second prosomal somite with dorsoposterior projection on third pedigerous somite in lateral view, with extended and pointed posterolateral corners and small protrusions on inner distal part in dorsal view, fourth pedigerous somite with secretory pores on each inner and outer pleural area (arrowed in Figure 7B View Figure 7 ).

Proportional lengths (%) of urosomites and caudal rami are 6.6: 59: 34.4. Genital double-somite ( Figure 7A,B View Figure 7 ) irregular, showing folds in dorsal view, 2.3 times longer than maximum width in middle of somite, round hump-like projection arising from anteroventral margin (visible in lateral view), bearing patch of spinules laterally ( Figure 7B,C View Figure 7 ), posteroventral and lateral margins fringed with minute spinules and denticles; posterior margin finely serrated ventrally, dorsoposterior surface often with two attached spermatophores.

Caudal rami ( Figure 7A,B,D View Figure 7 ) about 2.3 times shorter than genital double-somite, 3.5 times longer than maximum width. Caudal setation similar to that of F. concinna .

Antennule ( Figure 8A View Figure 8 ) similar to that of F. concinna . Proportional lengths (%) of segments measured along posterior non-setiferous margin 17.6: 13.5: 13.5: 28.4: 14.9: 12.1.

Antenna ( Figure 8B View Figure 8 ) similar to that of F. concinna but outer spine of third endopodal segment relatively shorter than that of F. concinna .

Mandible ( Figure 8C View Figure 8 ) similar to that of F. concinna .

Maxillule ( Figure 8D View Figure 8 ) similar to that of F. concinna , except innermost element (A) longest. In F. concinna second inner element longest

Maxilla ( Figure 8E View Figure 8 ) and maxilliped ( Figure 8F View Figure 8 ) similar to F. concinna .

Swimming legs 1–3 biramous (Figure 9A–C), with armature and ornamentation as in F. concinna .

Exopods of P1 to P3: length ratios of terminal spines to distal spines, in P1 and P2 2.6: 1, and P3 largest (2.8: 1), terminal spines longer than distal segments, in P1 1.2 times longer, in P2 about 1.4 times longer, and in P3 2.1 times longer.

Endopods of P1 to P3: proportional lengths of distal segments to terminal setae of P1 to P3 different, in P1 1: 2.1, and in P2, 1: 1.9, and in P3 1: 7.5.

Figure 9. Farranula gibbula . Female: (A) P1; (B) P2; (C) P3; (D) P4.

P4 (Figure 9D) similar to that of F. concinna , but proportional lengths of endopodal segments 35.7: 21.4: 42.9 and length ratio of distal segment to terminal spine 1.3: 1.

P5 similar to that of F. concinna (not figured)

P6 ( Figure 7E View Figure 7 ) represented by operculum closing off each genital aperture.

Male

Total body length in lateral view 863 µm (average: 833.5 µm, n = 7 individuals), measured from anterior margin of prosome to posterior margin of caudal rami. Urosome distinctly narrower than prosome ( Figure 10A,B View Figure 10 ).

Prosome ( Figure 10A,B View Figure 10 ) two-segmented, prosome length about 1.2 times longer than urosome including caudal rami, about 1.7 times longer than urosome excluding caudal rami; pleural areas extending quarter of length of urosome. Two large separate cuticular lenses located very close to each other on frontal margin.

Caudal rami 7.1 times longer than wide at base ( Figure 10A,B View Figure 10 ), longer than in female (3.5 times), about 2.5 times shorter as long as genital somite. Armature of rami similar to that of female, but caudal seta III longer than that of female.

Antenna ( Figure 11A View Figure 11 ) similar to that of F. concinna , but third endopodal segment with shorter and more robust spine on proximal inner margin and third endopodal segment longer, expanding to 80% of syncoxa, greater than in F. concinna (expanding to 67% of syncoxa).

Maxilliped ( Figure 11B View Figure 11 ) similar to that of F. concinna , except for basis bearing coarse setules between proximal third and medial seta, as compared with that of F. concinna . Distal endopodal segment (claw) relatively longer than in F. concinna .

Swimming legs 1–3 ( Figure 11C–E View Figure 11 ) similar in segmentation and armature to female, except proportional length of terminal spine to outer distal spine in P3, relatively longer (3.7 times) than in female (2.8 times).

P4 ( Figure 11F View Figure 11 ) similar to that of female, but length ratio of distal segment to terminal spine smaller (2: 1) than in female (1.3: 1).

P6 ( Figure 10B,C View Figure 10 ) with long plumose seta and ornamented with many denticles: proximal area with rows of denticles; inner distal area with large denticles; middle part of outer surface covered with patch of minute denticles.

Remarks

Females of F. gibbula from Korean waters closely match Giesbrecht’s (1893 [“1892”]: figs 22, 23) original description, and are characterized by a dorsoposterior projection on the second prosomal somite and uniquely shaped genital double-somite in both dorsal and lateral profile. In addition, the species is distinguished from other Farranula species by the following morphological characters: in the female 1) the outer spine of the third endopodal segment of the antenna is relatively shorter than that of F. concinna , 2) the innermost element A of the maxillule is longest, whereas in F. concinna it is shorter than the adjacent element B, 3) the ratio of the length of the distal spine on inner margin of basis of the maxilliped to length of the segment itself is smaller (2.6: 1) than that of F. concinna (3: 1), 4) the genital double-somite is ornamented with minute spinules and denticles on posteroventral and lateral margins; in the male 5) the pleural areas of the second prosomal somite extended over 25% of the length of the urosome, 6) caudal seta IV is longer than that of female, 7) the basis of maxilliped bears coarser setules on the margin proximal to the inner seta on the basis, 8) the length ratio of the terminal spine to the outer distal spine on the distal exopodal segment of P 3, is larger than that of female, 9) length ratio of the distal segment to the terminal spine of P4 exp-3, is smaller than that of female, and 10) the genital flap is ornamented with a unique pattern of denticles,