Anilocra brillae, Welicky, Rachel L., Hadfield, Kerry A., Sikkel, Paul C. & Smit, Nico J., 2017

Welicky, Rachel L., Hadfield, Kerry A., Sikkel, Paul C. & Smit, Nico J., 2017, Molecular assessment of three species of Anilocra (Isopoda, Cymothoidae) ectoparasites from Caribbean coral reef fishes, with the description of Anilocrabrillae sp. n., ZooKeys 663, pp. 21-43 : 28-34

Anilocra brillae sp. n. Figs 5, 6, 7, 8

Anilocra haemuli (Part) of Bunkley Williams and Williams (1981) [records from Serranidae ].

Material examined.

All material from the subocular region of Epinephelus guttatus .

Holotype. Ovigerous ♀ (38, 17, AMNH_IZC 250209), Lameshur Bay, St. John, 18°18'59"N, 64°43'25"W, US Virgin Islands, 2 Mar 1977, coll. EH and LB Williams.

Paratype. Ovigerous ♀ dissected (39, 15, AMNH_IZC 250210), Lameshur Bay, St. John, USVI, 2 Mar 1977 by EH and LB Williams.

Others examined.

Collected by EH and LB Williams: ♀ (33, 13, AMNH_IZC 250211; 24, 9) San Cristobal Reef, La Parguera, Puerto Rico 28-29 Jan 1977; ♀ (35, 15, AMNH_IZC 250212; 32, 13 AMNH_IZC 250213) Lameshur Bay, St. John, USVI, 2 Mar 1977; ♀ (39, 16, AMNH_IZC_250214) Buck Island, St. Thomas, USVI, 5 Mar 1977; ♀ (34, 15, AMNH_IZC 250215; 25, 10 AMNH_IZC 25016) Laurel Reef, La Parguera, Puerto Rico, 18 May 1977; ♀ (30, 12) Ensenada Honda, Vieques, Puerto Rico, 20 Dec 1983. Collected by PC Sikkel and ER Brill: ♀ (27, 10; 30, 13; 26, 10; 31, 12; 29, 12; 29, 12; damaged) TS (11,6) White Bay, Guana Island, 18°28'0"N, 64°33'59"W, BVI, Jul-Aug 2016.

Ovigerous female.Size (38, 17). Body ovoid, 2.1-2.4 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5, most narrow at pereonite 1, lateral margins mostly posteriorly ovate. Cephalon 0.5-0.7 times longer than wide, visible from dorsal view, trapezoid shaped. Frontal margin rounded to form blunt rostrum, not folded. Eyes oval with distinct margins, one eye width 0.1 times width of cephalon; one eye length 0.5-0.6 times length of cephalon. Pereonite 1 smooth, anterior border straight, anterolateral angle narrowly rounded, not produced. Posterior margins of pereonites smooth and slightly curved laterally. Coxae 2-3 wide with posteroventral angles rounded; 4-7 with narrowly produced point, curved; not extending past pereonite posterior margin. Pereonites 1-5 increasing in length and width; 6-7 decreasing in length and width; 5 and 6 subequal in width, 1-4 narrower. Pleon with pleonite 1 most wide, visible in dorsal view; pleonites posterior margin smooth, 1-4 posteriorly concave, 5 straight. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonite 1 differ in form to pleonite 4 and 5, similar to pleonite 2 and 3. Pleonite 5 equal width to pleonite 4, not overlapped by lateral margins of pleonite 4, posterolateral angles narrowly rounded, posterior margin straight. Pleotelson 1.1-1.4 times as long as anterior width, dorsal surface smooth, lateral margins convex, posterior margin converging to weak caudomedial point.

Antennula bases separated, shorter than antenna, consisting of 7-9 articles; peduncle articles 1 and 2 distinct and articulated; article 2 1.5 times as long as article 1; article 3 0.9 times as long as wide, 0.5 times as long as combined lengths of articles 1 and 2; flagellum with 4 articles, extending to posterior margin of eye. Terminal arti cle terminating in 1 short simple seta. Antenna comprised of 9-10 articles, peduncle article 3 1.5 times as long as article 2; article 4 1.3 times as long as wide, 1.1 times as long as article 3; article 5 1.6 times as long as wide, 1.1 times as long as article 4; flagellum with 4 articles, terminal article with 5 short simple setae, extending to posterior of pereonite 1. Mandibular molar process ending in an acute incisor; mandibular palp article 3 with 8 simple setae. Maxillula simple with 4 terminal robust setae. Maxilla mesial lobe partly fused to lateral lobe; lateral lobe with 2 recurved robust setae; mesial lobe with 1 recurved robust seta. Maxilliped weakly segmented, with lamellar oostegite lobe, article 3 with 3 recurved robust setae.

Pereopod 1 basis 1.8 times as long as greatest width; ischium 0.23 times as long as basis; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus 1.9 times as long as wide; dactylus moderately slender, 1.8 times as long as propodus, 3.7 times as long as wide. Pereopod 2 propodus 1.7 as long as wide; dactylus 2.7 times as long as propodus, 4.9 times as long as wide. Pereopods gradually increasing in size towards posterior. Pereopod 6 basis 1.7 times as long as greatest width; ischium 0.7 times as long as basis; propodus 1.5 times as long as wide, dactylus 2.3 times as long as propodus, 3.8 times as long as wide. Pereopod 7 basis 3.0 times as long as greatest width; ischium 0.7 times as long as basis, without protrusions; merus proximal margin without bulbous protrusion, 2.0 times as long as wide, 0.7 times as long as ischium; carpus 1.5 times as long as wide, 0.6 times as long as ischium, without bulbous protrusion; propodus 3.2 times as long as wide, 0.8 times as long as ischium; dactylus moderately slender, 0.9 times as long as propodus, 3.5 times as long as wide. Pereopod 7 with many setae on propodus, carpus, and merus.

Pleopods without setae, exopod larger than endopod. Pleopod 1 exopod 1.2 times as long as wide, lateral margin weakly convex, distally narrowly rounded, medial margin weakly oblique, mesial margin weakly convex; endopod 1.8 times as long as wide, lateral margin weakly convex, distally narrowly rounded, mesial margin slightly convex, peduncle 2.2 times as wide as long, with pointed projection on lateral margin. Pleopods 2-5 similar to pleopod 1. Pleopods 3-5 endopods proximal borders do not extend below exopod to peduncle, fleshy lobes and medial lobes present. Peduncle lobes absent.

Uropod more than half the length of pleotelson, peduncle 0.7 times longer than rami, peduncle lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices broadly rounded. Endopod apically rounded, 2.2 times as long as greatest width, lateral margin weakly convex, mesial margin weakly convex, terminating without setae. Exopod not extending to end of endopod, 2.6 times as long as greatest width, apically rounded, lateral margin convex, mesial margin weakly convex or weakly concave, terminating without setae.

Transitional stage.

Size (11, 6). Similar to female but smaller. Body 2.6 times as long as wide. Antennula bases separated, consisting of 8 articles, extending to middle of eye. Antenna consisting of 10 articles, extending to middle of pereonite 1. Mandibular molar process ending in an acute incisor; mandibular palp article 2 with 2 simple setae, article 3 with 7 simple setae. Maxillula simple with 4 terminal robust setae. Maxilla mesial lobe partly fused to lateral lobe; lateral lobe with 2 recurved robust setae; mesial lobe with 2 recurved robust setae. Maxilliped weakly segmented, with lamellar oostegite lobe, article 3 with 3 recurved robust setae. Pereopod 7 with several small robust setae on carpus, merus and propodus. Pleopod 2 appendix masculina absent.

Etymology.

This species is named in honor of Elizabeth R. Brill for her dedication to studying the ecology of A. haemuli , and for collecting many of the A. haemuli and A. brillae sp. n. specimens used in this study.

Distribution.

Known from St. John and St. Thomas, USVI, Guana Island, BVI, and islands of Puerto Rico, Spanish Virgin Islands. Expected distribution throughout the Caribbean Sea, where fish of the Serranidae family inhabit.

Hosts.

Known from Epinephelus guttatus (Linnaeus, 1758).

Remarks.

Previously, A. brillae sp. n. was identified as A. haemuli . Compared to A. haemuli , the outer margins of the cephalon and pereonites 1-4 of A. brillae sp. n. form a more pronounced trapezoid shape and the remaining portion of the body is ovoid. A. brillae sp. n has more strongly narrowed pleonites than A. haemuli . Pleonites 1-3 of A. brillae sp. n. are wider than 4-5 and 4-5 are subequal, whereas the pleonites 1-2 of A. haemuli are wider than 3-5, and 3-5 are subequal. Pleonite 5 is more posteriorly rounded in A. brillae sp. n, but this is somewhat variable among individuals. Another more variable feature is A. brillae sp. n. has a more caudomedially pointed pleotelson than A. haemuli . Typically, the seventh pereopod of A. brillae sp. n. is proportionally larger, has more robust setae, and the setae are distributed more extensively over the articles when compared to A. haemuli . The antennula peduncle of A. brillae sp. n. is regularly observed as shorter and more robust than that of A. haemuli . With respect to attachment, both species infest the subocular region, and if infested by two parasites, one parasite typically attaches under each eye. Infestation by a third A. brillae sp. n. on a single host seems to occur with more frequency than tertiary infestation by A. haemuli on a single host. The third parasite is typically attached between the eyes on the head of the host, or adjacent to one of the other parasites (RLW, pers obs).

Anilocra brillae sp. n. can be distinguished from all other Caribbean species except Anilocra haemuli using the same morphological comparisons described between A. haemuli and other Anilocra spp. given in Bunkley Williams and Williams (1981). Additionally, the body of A. brillae sp. n. is not expanded and is more elongate compared to the bodies of A. holocanthi and A. chaetodontis .