Pulchrascaris sp.

Gonzalez-Solis, David, Soler-Jimenez, Lilia C., Aguirre-Macedo, M. Leopoldina, McLaughlin, John P., Shaw, Jenny C., James, Anna K., Hechinger, Ryan F., Kuris, Armand M., Lafferty, Kevin D. & Vidal-Martinez, Victor M., 2019, Parasitic nematodes of marine fishes from Palmyra Atoll, East Indo-Pacific, including a new species of Spinitectus (Nematoda, Cystidicolidae), ZooKeys 892, pp. 1-26 : 1

Pulchrascaris sp.

Description.

Third-stage larva (12 specimens): relatively long nematodes 6.99-12.42 mm long and 172-452 wide, whitish with lateral cuticular alae. Lips weakly developed and bearing a larval, ventral tooth, 5-12 long. Nerve ring encircling esophagus in its anterior third, 173-302 from anterior body end. Deirids slightly posterior to nerve ring, 225-273 from cephalic end. Excretory pore at base of subventral lip. Esophagus relatively long, 636-1,414 with elongated ventriculus at posterior end, 388-1,371 long. Intestinal caecum anteriorly directed and somewhat larger than ventriculus, 389-1,384 long. Tail conical, 99-179 long, without ornamentations. Some specimens with a single papilla at 1.65-5.78 mm from posterior end of body.

Hosts.

Acanthurus sordidus , A. triostegus , Acanthurus xanthopterus Valenciennes ( Acanthuridae ), Rhinecanthus aculeatus (Linnaeus) ( Balistidae ), Platybelone argalus argalus (Lesueur) ( Belonidae ), C. ferdau , Carangoides orthogrammus (Jordan & Gilbert), Caranx ignobilis ( Forsskål), Caranx melampygus Cuvier, Caranx papuensis Alleyne & MacLeay (all Carangidae ), Amblygobius phalaena (Valenciennes), Asterropteryx semipunctata Rüppell, Valenciennea sexguttata (Valenciennes) (all Gobiidae ), M. flavolineatus , Upeneus taeniopterus Cuvier ( Mullidae ), Gymnothorax pictus (Ahl) ( Muraenidae ), L. fulvus , Lutjanus monostigma (Cuvier) ( Lutjanidae ), Abudefduf septemfasciatus (Cuvier), Stegastes nigricans ( Lacepède) ( Pomacentridae ), C. auriga , C. chanos , K. cinerascens , E. vaigiensis .

Site of infection.

Mesenteries.

Prevalence and mean intensity.

5.6 and 1 (n = 18) to A. sordidus , 8 and 2.3 ± 1.9 (n = 50) to A. triostegus , 15 and 1.3 ± 0.6 (n = 20) to A. xanthopterus , 11.1 and 1 (n = 18) to R. aculeatus , 50 and 10 (n = 2) to P. argalus , 40 and 42 ± 58 (n = 5) to C. ferdau , 66.7 and 52.5 ± 72.8 (n = 2) to C. orthogrammus , 100 and 71.3 ± 106.5 (n = 4) to C. ignobilis , 100 and 53.7 ± 106.4 (n = 6) to C. melampygus , 40 and 8 ± 9.9 (n = 5) to C. papuensis , 33.3 and 7.2 ± 8.6 (n = 18) to A. phalaena , 8.3 and 3 (n = 12) to A. semipunctata , 7.1 and 1 (n = 14) to V. sexguttata , 9.6 and 1.4 ± 0.4 (n = 52) to M. flavolineatus , 60 and 3.7 ± 1.5 (n = 5) to U. taeniopterus , 14.3 and 3 (n = 7) to G. pictus , 46.2 and 5.2 ± 3.7 (n = 26) to L. fulvus , 50 and 4.7 ± 3.2 (n = 6) to L. monostigma , 8.3 and 1 (n = 12) to A. septemfasciatus , 10 and 1 (n = 10) to S. nigricans , 7.7 and 1 (n = 13) to C. auriga , 20 and 2 (n = 5) to C. chanos , 50 and 7 (n = 2) to K. cinerascens , 7.4 and 1.5 ± 0.6 (n = 54) to E. vaigiensis .

Specimens deposited.

CHCM no. 620 (voucher) (1 vial, 1 specimen ♀) (from A. triostegus ), CHCM no. 621 (voucher) (1 vial, 2 specimens ♂ ♀) (from C. auriga ), CHCM no. 622 (voucher) (1 vial, 1 specimen ♀) (from K. cinerascens ), CHCM no. 623 (voucher) (1 vial, 1 specimen ♀) (from L. fulvus ).

Remarks.

These larvae belong to the genus Pulchrascaris because of the position of the excretory pore between the subventral lips, absence of ventricular appendage, elongate esophagus, relatively large ventriculus, and intestinal caecum anteriorly directed and somewhat larger than ventriculus. Deardorff (1987) mentioned that differentiation of third stage larvae of the genera Pulchrascaris and Terranova is difficult, since lips are not well developed at that stage. We found one adult male, a young female and one larva of the species P. chiloscyllii in the blacktip reef shark C. melanopterus , which occurs in the same area and feeds on some small reef fishes ( Froese and Pauly 2014). Larvae identified as Pulchrascaris sp. are identical to those in the shark, and they could belong to the same species, but until studies on the life cycle or molecular analysis are carried out, we considered them as separate taxa. All fishes reported here probably act as intermediate or paratenic hosts and elasmobranchs are the definitive hosts. Jabbar et al. (2012) reported larval anisakid nematodes from several teleosts from the Great Barrier Reef, including larvae named as Terranova sp. type II in C. papuensis . Those nematodes differ from the present ones in the length and ratio of the intestinal caecum and ventriculus. Larval nematodes reported as Terranova sp. type I and Terranova sp. type Hawaii B (HB) ( Cannon 1977; Deardorff et al. 1982; Palm and Bray 2014) should be considered as Pulchrascaris sp. according to the ratios of their esophageal appendages. All fish parasitized by these larvae in the present work represent new host records.