Atortus, Ohtsuka, 1992

Francis, Sanu Vengasseril & Nandanb, Sivasankaran Bijoy, 2019, A new species of Tortanus (Atortus) (Copepoda, Calanoida, Tortanidae) from Minicoy Island, southeastern Arabian Sea, Turkish Journal of Zoology 43 (5), pp. 425-436 : 433-434

Key to the species of subgenus Atortus from the Indian Ocean:

Adult females: 1. Genital compound somite asymmetrical ................. 2

2. Genital compound somite right anterolateral margin slightly swollen ........................................... T. andamanensis

3. Caudal rami slightly asymmetrical with left ramus stouter and shorter than the right one ............... T. insularis

4. Genital compound somite with a bulge on the left or right side ................................................................................. 5

- Genital compound somite strongly asymmetrical, with the pointed process on the right ventrolateral side .... .............................................................................. T. magnonyx

5. Genital compound somite expanded anterolaterally on both sides ending in small papilla with apical spinule, right expansion strongly convex to straight laterally .......... .............................................................................. T. recticauda

6. Genital compound somite with a small bulge on the left side, caudal rami asymmetrical with left ramus stouter and right ramus slightly curved, fifth leg with spine at distal end ................................................................ T. tropicus

- Genital compound somite with a prominent bulge on the right side with 2 dorsoventral spines, caudal rami asymmetrical with left ramus slightly larger and right ramus not curved, fifth legs without spines at distal end .... ........................................................... T. minicoyensis sp. nov.

Adult males:

1. Left leg 5 subdistal seta strongly curved along hemispherical tip with the granular surface, and right coxa of leg 5 truncate with an uncinated corner, basis bearing medial bilobed process near midlength ................................ .............................................................................. T. recticauda

2. Left leg 5 with subdistal spiniform terminal seta, and right leg coxa produced into the rectangular process, basis bearing rounded, flattened process located at inner distal corner ...................................................................... T. nishidai

3. Right leg 5 coxa without any process ........................ 4

- Basis bearing small rounded process ........... T. tropicus

4. Left leg 5 subdistal seta serrated along inner margin, and right leg 5 basis tapering proximally with triangular process ................................................................ T. magnonyx

5. Left leg 5 terminal portion of second exopodal segment acutely pointed at tip, with serrated subdistal seta, and right leg 5 coxa bearing 3 acutely pointed prominences of unequal size, basis bearing large bilobed process at midlength .............................................................. T. insularis

6. Left leg 5 with subdistal blunt seta, and right leg 5 coxa semispherical with semispherical medial process, basis semicircular with the medial process being ocarinashaped with depression on distomedial margin and with small rounded process at distal side of its base ................. ....................................................................... T. andamanensis

7. Left leg 5 with subdistal short seta, and right leg 5 coxa semicircular with small bilobed medial process, basis semicircular with fingerlike medial process ..... T. sigmoides

8. Left leg 5 subdistal seta strongly curved along hemispherical tip with the granular surface, and right leg 5 coxa semitrapezoid with a beak-shaped medial process, basis semicircular and bearing triangular medial process .. ............................................................ T. minicoyensis sp. nov.

Nomenclatural acts: This work and the nomenclatural acts it contains have been registered in ZooBank. The ZooBank Life Science Identifier ( LSID) for this publication is: urn:lsid:zoobank.org:pub:3F2596B8-E1F9-4321-9157-BED7BC773638

Acknowledgments

This study was funded by the Department of Biotechnology of the Government of India [BT/PR4258/AAQ/3/575/2011]. The authors are thankful to the Head of the Department of Marine Biology, Microbiology, and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology for facilities given, and gratefully acknowledge the assistance rendered by the Department of Science and Technology, Lakshadweep. Thanks also to the research fellowship provided to SVF under the University Grants Commission Basic Science Research Program of the Government of India. Special thanks are due to Dr Shuhei Nishida, Atmosphere and Ocean Research Institute, University of Tokyo, for specimen identification and initial preparation of the manuscript.