Agarna malayi Tiwari 1952 (Crustacea: Isopoda: Cymothoidae) Parasitising the Marine Fish, Tenualosa toli (Clupeidae) from India: Re-description/description of Parasite Life Cycle and Patterns of Occurrence

Abstract

Panakkool Thamban Aneesh, Kappalli Sudha, Ameri Kottarathil Helna, and Gopinathan Anilkumar (2018) This paper re-describes the female stage of Agarna malayi Tiwari 1952, a protandrically hermaphroditic parasitic cymothoid, and describes the remaining life cycle stages for the first time. The re-description (female phase) of A. malayi was made based on the type specimens deposited by Tiwari (1952) in the National Zoological Collections of the Zoological Survey of India (NZC-ZSI) and data obtained from several live specimens collected from Ayyikkara Fish Landing Centre (11°51'N, 75°22'E, of Malabar Coast, India) and Marina Beach (13.0500°N, 80.2824°E, Bay of Bengal, India). General morphology, mouthparts and appendages of the species' life cycle stages such as larvae, juveniles, male and transitional stages are also reported for the first time. We closely observed 80 marine fish species belonging to 35 different families to identify the potential host of A. malayi, and only recovered the parasite from one fish, Tenualosa toli, signifying A. malayi's oligoxenous host specificity; the prevalence and intensity of parasitisation is 17.3 and 1.86%, respectively. The present paper also discusses sequential life cycle stages of the species.

Keywords: Clupeid fish; Host-parasite interaction; India; Lifecycle; Parasitic cymothoid.

Fig. 1.

Fig. 1. Photographs of the holotype and paratype of Agarna malayi Tiwari 1952 specimens studied: (A) holotype (C3121/2) dorsal view; (B) holotype (C3121/2) ventral view; (C) paratype (C3122/2) dorsal view; (D) paratype (C3122/2) ventral view; (E) branchial cavity of Nematalosa nasus, showing the holotype (C3122/2) in situ; (F) branchial cavity of Nematalosa nasus, showing the paratype (C3122/2) in situ.

Fig. 2.

Fig. 2. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes). (A-B) male dorsal and ventral view; (C-D) transitional stage dorsal and ventral view; (E-F) ovigerous female dorsal view; (G) manca II larva; (H) juvenile; (I) ovigerous female on T. toli; (J) manca II on T. toli.

Fig. 3.

Fig. 3. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) ovigerous female, (A-B) dorsal view; (C) ventral view; (D) antennule; (E) antenna; (F) mandible; (G) maxillule; (H) maxilla; (I) maxilliped.

Fig. 4.

Fig. 4. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) ovigerous female, (A-G) pereopods 1-7; (H) brood; (I) pleopod 2; (J) pleopod 5; (K) uropod; (L) pleotelson and uropods.

Fig. 5.

Fig. 5. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) transitional stage, (A) dorsal view; (B) mandible; (C) maxillule; (D) maxilla; (E) maxilliped; (F) pleopod 2.

Fig. 6.

Fig. 6. Agarna malayi Tiwari 1952 ex Tenualosa toil (Valenciennes) male (A) dorsal view; (B) ventral view; (C) antennule; (D) antenna; (E) mandible; (F) maxillule; (G) maxilla; (H) maxilliped.

Fig. 7.

Fig. 7. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) male, (A-G) pereopods 1-7; (H-L) pleopods 1-5; (M) pleotelson and uropods.

Fig. 8.

Fig. 8. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) juvenile, (A) dorsal view; (B) antennule; (C) antenna; (D) mandible; (E) maxillule; (F) maxilla; (G) maxilliped.

Fig. 9.

Fig. 9. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) juvenile, (A-G) pereopods 1-7; (H) pleopod 2; (I) pleopod 4; (J) uropod; (K) pleotelson and uropods.

Fig. 10.

Fig. 10. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) manca II, (A) dorsal view; (B) antennule; (C) antenna; (D) mandible; (E) maxillule; (F) maxilla; (G) maxilliped.

Fig. 11.

Fig. 11. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes) manca II, (A-C) pereopods 1-3; (D-E) pereopod 5-6; (F) pleopod 1; (G) pleopod 5; (H) uropod; (I) pleotelson and uropods.

Fig. 12.

Fig. 12. Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes), manca I, (A) dorsal view; (B) antennule; (C) antenna; (D) mandible palp; (E) maxillule; (F) maxilla; (G) maxilliped; (H) pereopod 1; (I) pleopod 2; (J) pleotelson and uropods.

Fig. 13.

Fig. 13. Schematic representation of the life cycle of Agarna malayi Tiwari 1952 ex Tenualosa toli (Valenciennes); Abbreviations: Manca II (F), manca II at free living stage; Manca II (I), manca II at infective stage; ES, embryonic stage; Fs, female stage.

Fig. 14.

Fig. 14. Marsupiumites showing six morphologically distinct ontogenic stages sequentially as zygotic stage (a); three embryonic stages (ES-1 (b), ES-II (c) and ES-III (d)); and two larval stages (manca I (e) and manca II (f)).