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Marine Planktonic Copepods
Cymbasoma cheni  Lian & Tan, 2019   (F)
Taxonomy
Order Monstrilloida
Family Monstrillidae

References

Lian & Tan, 2019 (p.1709, Descr.F, figs.F, Rem., Table 2: comparison with other species )

Figures

Plate 1 Issued from : X. Lian & Y. Tan in J. Oceanol Limnol, 2019, 37 (5). [p.1010, Fig.2, B, C]
Female (from 25.09°N, 119.08°E); B-C, habitus (dorsal and lateral, respectively).

Nota:
- Cephalothorax accounting for 66% of body length.
- Oral papilla midventrally 0.28 mm of the way back along cephalothorax.
- Pair of relatively large ocelli, rounded, pigment cups moderately developed , medially conjoined, intensely pigmented at inner margins only.
- No cuticular ornamentation observed on the remaining surface of the cephalothorax.
- Cephalothorax incorporating 1st thoracic pedigerous somite. 1st thoracic pediderous somite and 3 free succeeding pedigerous somites , each bearing pair of legs. Pedigerous somites 2-4 accounting forv 21.8% of total body length in dorsal view.
- Urosome consisting of 5th pedigerous somite, genital double-somite and 1 free abdominal somite (anal). Ratio of lengths35.6 : 44.7 : 19.7 = 100. Urosome accounting for 12.2% of total body length.
- Genital double-somite almost half-length of urosome (44.7%); medial portion moderately swollen, smooth dorsal and ventral surfaces .
- Pair of long ovigerous spines, insert on the middle of the ventral surface, basally separated , representing 36.7% of total body length.
- Anal somite smooth both on dorsal and ventral surfaces, witout obvious notch.
- Caudal rami 2.0 times longer than wide, bearing 3 naked terminal setae
Plate 2 Issued from : X. Lian & Y. Tan in J. Oceanol Limnol, 2019, 37 (5). [p.1010, Fig.3]
Female: a-b, left and right A1 (dorsal view); c, P5 (ventral view); d, P1; c, P2; f, caudal rami (ventral view).

Nota:
- A1 relatively long, 0.33 mm, about 26.3% of the cephalothorax and about 17.3% of total body length. 4-segmented (length ratio of segments, from basal to distal: 11.4 : 18.2 : 20.5 : 49.9 = 100), armed with 1, 0; 1, 1; 1, 1; 4, III setae. Armature element 1 present on segment 1:1d1. Segment 2 with 2d1 and IId. Segment 3 with elements 3: 3d1 and IIId. Segment 4 bearing element 4d1, 4v1-3. Element 5 absent. Last segment with one small aesthetasc on distal margij. 6 (1) and 6 (2) present.
- P5 single lobed, medially separated, each lobe with 1 segment (1.5 times longer than wide). Lobe armed with 3 naked setae, subequal in length and breath.
Plate 3 Issued from : X. Lian & Y. Tan in J. Oceanol Limnol, 2019 (37 (5) [p.1011, Table 1]
Female: Armature of swimming legs.
Plate 4 Issued from : X. Lian & Y. Tan in J. Oceanol Limnol, 2019, 37 (5). [p.1011, Table 2]
Comparison of main characters in 9 similar species (elongate cephalothorax and P5 with 1 lobe) of Cymbasoma females only.

Distribution

NZ: 1

Distribution map of Cymbasoma cheni by geographical zones


Localisations

S. China (Meizhou Bay, Fujian

Type locality: 25.09° N, 119.08° E.

Quotations

N: 1

Dimensions (mm)

(1231)* F: 1,9; [F: 1,9]
*: total body length measured from anterior end of head to posterior margin of abdominal somite.

Remarks

New species closely related to Cymbasoma bowmani, species collected by Suarez-Morales & Gasca (1998) in a reef area on the Yucatan Peninsula (Mexico). For the authors, another species that merits mentioing is Cymbasoma quintanarooense Suarez-Morales (1994) because it also has P5 with a single lobe armed with 3 setae subequal in length and breath; however, the new species C. cheni can be distinguished by several other characters.
Last update : 19/06/2023

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