Prionodiaptomus colombiensis Thiébaud, 1912

Gutiérrez-Aguirre, Martha Angélica & Suárez-Morales, Eduardo, 2000, New extension range of the diaptomid copepod Prionodiaptomus colombiensis Thiébaud, 1912 (Copepoda, Calanoida) with complementary description of this species, Zoosystema 22 (3), pp. 507-516 : 511

Prionodiaptomus colombiensis Thiébaud, 1912

( Figs 1-4 )

MATERIAL EXAMINED. — Laguna Matillas . Tabasco, Mexico, 12.I.1998, 2 adult, ethanol-preserved ( MNHN-Cop1778 ), 5 adult, ethanol-preserved ( ECOCH-ZOO-00676 ), 2 adult, ethanol-preserved, undissected ( MNHN-Cop1779 ), 4 adult ( ECOCH-ZOO-00675 ).

LOCALITY. — Laguna Matillas . Tabasco, southeastern Mexico, 17°53’45.8”N, 92°31’19.6”W, 12.I.1998, water temperature 27.7°C; pH 6.32; oxygen 7.2 ppt.

DESCRIPTION

Body shape and proportions of males and females as described and depicted by Kiefer (1956), Gaviria (1989), and Dussart & Defaye (1995) ( Figs 1A, C ; 3A ; 4A ). Mean length (n = 7) of females: 1.32 mm (1.30-1.33 mm), cephalothorax 0.97 mm long, 0.42 mm wide, with usual spiniform processes ( Fig. 3B ). Rostrum strong, bifid ( Fig. 3C ). Urosome 0.35 mm long ( Fig. 2B ).

Antennules 0.98 mm long. Genital somite 2 or 3- segmented, 0.21mm long, 0.13 mm wide, 59% of urosome length. Urosome 26% of total body length. Female genital operculum ( Figs 2C ; 3F ) with wide, curved proximal plate, posterior end with strong, inwards curved lateral arms. Mean length (n = 6) of males: 1.09 mm (1.03- 1.18 mm), cephalothorax 0.78 mm long, 0.33 mm wide. Left antennule 0.91mm long.

Urosome 0.31mm, 28% of total body length.

Antennules female ( Fig. 1B )

Relatively short, 25-segmented, reaching posterior margin of fifth pedigerous somite or even posterior margin of anal somite in some specimens. Long setae on segments 3, 11, 14, 18, 21, 23-25. Setae on segments 16, 18, 21, 22-25 biserially plumose on distal 1/3. Appendages per segment as follows (Arabic numerals, segment; Arabic numerals between brackets, number of setae; ae, aesthetasc; sp, spine): 1(1), 2(3+1ae), 3(1+1ae), 4(1), 5(1+ae), 6(1), 7(1+ae), 8(2), 9(1+ae), 10(2), 11(1), 12 (1+ae), 13(1), 14(1+ae), 15-18(1), 19(ae), 20(1), 21(1), 22(1+ae), 23(2), 24 (2), 25(3).

Antennules male ( Figs 1D ; 4E )

22-segmented, left antennule as in female, but relatively shorter, reaching posterior margin of first urosomite. Right antennule broadened between segments 13-17. Appendages per segment as follows: 1(1), 2(2), 3(1), 4(1), 5(1), 6(1), 7(1), 8(1+sp), 9(3), 10(1+sp), 11(1+sp), 12(2), 13(1+sp), 14(2), 15(2), 16(2), 17-18(0), 19(1), 20(2), 21(1), 22(4). Large spine-like processes on segments 8, 10, 11, and 13. Process on segment 11 largest, reaching distal margin of segment 13 ( Figs 1E ; 4E ). Low, broad-based spine on segments 12, 15, and 16, spine on 16 slightly larger than that on 15.

Fifth legs female and male ( Figs 2A , D-F; 3D, E; 4B-D).

In general, as described and depicted by Gaviria (1989), Kiefer (1956), Wilson & Yeatman (1959), and Dussart & Defaye (1995). In the female, the large spine on the third exopodal segment of the fifth leg is relatively longer in our specimens than in other descriptive works considered. Moreover, there are differences in the length ratios of the fifth female leg and in the number of urosomites ( Table 1 ). In the male, other slight differences were noted when our specimens were compared with published illustrations and descriptions ( Table 1 ).

Figures

FIG. 1. — Prionodiaptomus colombiensis Thiébaud, 1912; A, habitus dorsal, female; B, antennule, female; C, habitus dorsal, male; D, right antennule, male; E, right antennule, segments 8-13 (only spines are illustrated), male. Scale bars: A, C, 0.5 mm; B, D, 0.17 mm; E, 0.12 mm.

FIG. 2. — Prionodiaptomus colombiensis Thiébaud, 1912; A, fifth legs anterior view, female; B, urosome dorsal view, female; C, genital somite ventral, female; D, fifth legs anterior view, male; E, detail of left leg exopod and endopod, male; F, detail of right leg basipod and first exopodal segment, male. Scale bars: A, 0.1 mm; B-D, 0.23 mm; E, 0.08 mm; F, 0.12 mm.

FIG. 3. — Prionodiaptomus colombiensis Thiébaud, 1912, adult female; A, habitus dorsal view; B, posterolateral margins in the fifth pediger and urosome; C, rostrum; D, fifth legs posterior view, showing the spines on the coxopodite; E, fifth leg terminal segment, detail; F, genital field, showing seminal receptacle. Scale bars: A, 125 µm; B, 50 µm; C, 11.5 µm; D, 20 µm; E, 10 µm; F, 9 µm.

FIG. 4. — Prionodiaptomus colombiensis Thiébaud, 1912, adult male; A, habitus dorsal view; B, fifth legs, posterior view, showing coxal spines; C, fifth leg second right exopod, showing aculeus; D, right fifth leg, showing endopod; E, antennule. Scale bars: A, 100 µm; B, 13.3 µm; C, 20 µm; D, 6.6 µm; E, 7 µm.