Bambalocra intwala, Bruce, Niel L., Welicky, Rachel L., Hadfield, Kerry A. & Smit, Nico J., 2019

Bruce, Niel L., Welicky, Rachel L., Hadfield, Kerry A. & Smit, Nico J., 2019, A new genus and species of fish parasitic cymothoid (Crustacea, Isopoda) from the Indian Ocean coast of South Africa, with a key to the externally attaching genera of Cymothoidae, ZooKeys 889, pp. 1-15 : 1

Bambalocra intwala sp. nov. Figures 1 , 2 , 3 , 4 , 5

Material examined.

Holotype: South africa • 1 ♀ (ovigerous, 23.5 mm TL, 12 mm W); Sodwana Bay, Kwazulu-Natal; 27°32'S, 32°41'E; April 1979; host not recorded, coll. R.E. Stobbs; SAMC-A091364.

Paratypes: South africa • 1 ♂ (immature, 7.5 mm TL, 3.0 mm W) 3 ♀♀ (23-24 mm TL, 11.0-12.0 mm W); same data as holotype; SAMC-A091365 • 1 ♀ (20.0 mm TL, 11.0 mm W); Sodwana Bay, Kwazulu-Natal; 27°30'S, 32°41'E; 12.8 m depth; July 1976; host not recorded, coll. Richard Winterbottom (RW 76-14); SAMC-A091366 • 1 ♀ (21.0 mm TL, 11.5 mm W); Durban Sea World; September 2003; from a dwarf angelfish ( Centropyge ); SAMC-A091367.

Description of female

(from holotype and 23.0 mm female paratype). Body oval, 1.9 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 5, narrowest at pereonite 1; lateral margins ovate. Cephalon 0.7 times longer than wide, frontal margin broadly truncate. Eyes oval with distinct margins, eye width 0.2 times width of cephalon. Pereonite 1 anterior border anteriorly concave, anterolateral angles narrowly rounded. Coxae 2 and 3 narrow with posteroventral angles with small distinct produced point; coxae 4-7 with small, distinct dorsally directed point, not extending past pereonite margin. Pereonites 4-7 with posteroventral angle weakly produced, acute; pereonite 7 posterolateral margins extending to pleonite 3. Pleon 0.4 times as wide as pereon. Pleonites posterior margin evenly concave; pleonite 1 widest, visible in dorsal view; pleonite 2 partially overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3-5 similar in form to pleonite 2; pleonite 5 not overlapped by lateral margins of pleonite 4, posterior margin slightly concave. Pleotelson 0.8 times as long as anterior width, dorsal surface smooth, lateral margins convex, posterior margin evenly rounded.

Antennula length shorter than antenna, extending to anterior of pereonite 1, consisting of 8 articles; peduncle articles 1 and 2 distinct and articulated; article 2 1.7 times as long as article 1; 0.4 times as long as combined lengths of articles 1 and 2. Antenna extending to anterior margin of pereonite 1, consisting of 8 articles; article 3 1.4 times as long as article 2; article 4 1.4 times as long as article 3; article 5 1.4 times as long as article 4; terminal article with 3 short simple setae distally.

Mandibular molar process present, small; palp article 3 with 3 simple setae. Maxillula with lateral RS largest. Maxilliped palp consisting of 3 articles, with lamellar oostegite lobe; article 2 without setae, article 3 with 3 recurved short RS.

Pereopod 1 basis 1.7 times as long as greatest width; ischium 0.5 times as long as basis; merus proximal margin without bulbous protrusion; propodus 1.5 times as long as wide; dactylus moderately slender, 1.3 times as long as propodus, 3.2 times as long as basal width. Pereopod 2 propodus 1.4 times as long as wide; dactylus 1.5 times as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 basis 2.1 times as long as greatest width, ischium 0.3 times as long as basis; propodus 1.2 times as long as wide; dactylus 2.1 times as long as propodus. Pereopod 7 longer than other pereopods, slightly longer than pereopod 6; basis 2.3 times as long as greatest width; ischium 0.7 times as long as basis, without protrusions; merus proximal margin without bulbous protrusion, as long as wide, 0.4 times as long as ischium; carpus 1.2 times as long as wide, 1.1 times as long as ischium, without bulbous protrusion; propodus 1.9 times as long as wide, 1.4 times as long as ischium; dactylus moderately slender, 1.6 times as long as propodus, 3.5 times as long as basal width.

Pleopods 1 and 2 rami simple, 3-5 endopods with weak fleshy ridges. Pleopod 1 exopod 1.4 times as long as wide, lateral margin weakly convex, distally broadly rounded, mesial margin weakly convex; endopod 1.2 times as long as wide, lateral margin convex, distally broadly rounded, mesial margin slightly convex; peduncle 2.8 times as wide as long. Pleopod endopods 3-5 each with proximomedial lobe.

Uropod 0.8 times as long as pleotelson; peduncle 0.7 times as long as rami, lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices broadly rounded. Endopod 2.9 times as long as greatest width, as long as exopod, lateral margin convex, mesial margin straight. Exopod extending to end of endopod, 3.1 times as long as greatest width, lateral margin convex.

Male

(juvenile paratype 7.5 mm). Body approximately 2.0 times longer than wide; posterolateral margins of pereonites laterally extending giving indented body outline; coxae posteriorly acute; pereonite 7 extending to posterior of pleonite 2. Pleon half as wide as body, all pleonites visible in dorsal view. Pleotelson 0.9 times as long as anterior width, lateral margins convex, posterior margin evenly rounded.

Antennula with 8 articles. Antenna with 10 articles. Mandible article 3 with 6 RS. Pereopods similar in proportions to female. Pleopods similar in proportions to female; pleopod 2 appendix masculina and penial processes absent.

Uropod 0.8 as long as pleotelson, peduncle 0.5 times as long as rami, rami not extending beyond pleotelson, apices narrowly rounded. Endopod 4.0 times as long as greatest width, 0.8 as long as exopod, lateral margin weakly convex, mesial margin weakly concave. Exopod extending beyond end of endopod, 4.7 times as long as greatest width, lateral margin convex, mesial margin concave.

Remarks.

As the genus is monotypic, the species is identified by the generic characters, in particular the coxae being ventral in position rather than lateral, the pleonites being all wide, without ventrolateral processes, in combination with the short posteriorly directed ventral rostrum that separates the slender antennula and antenna.

Host.

There is no host data for the holotype and wild-caught paratypes; the specimen from the Durban Aquarium is from a dwarf angelfish ( Centropyge ). Several species of externally attaching cymothoid have been photographed by SCUBA divers on the coral reefs at Sodwana Bay; from the photographs three species of Pomacanthidae (angelfish) are identified as probable hosts: Apolemichthys trimaculatus (Cuvier, 1831), Pomacanthus imperator (Bloch, 1787), and Pygoplites diacanthus (Boddaert, 1772), but these hosts need to be confirmed by direct capture of the isopods in situ.

Etymology.

The epithet is the word for louse ( intwala ) in the isiZulu language (noun in apposition).

Figures

Figure 1. Bambalocra intwala sp. nov. Holotype, 23.5 mm (SAMC-A 091364) A dorsal view B dorsal view, head, pereonite 1 C pleotelson D pleonites, lateral view E lateral view.

Figure 2. Bambalocra intwala sp. nov. Female paratype, 23.0 mm (SAMC-A 091365) A dorsal view B coxae, ventral view C pleonites, ventral view (pleopods removed) D frons E antennula F antenna G maxilla apex H mandible I maxillula apex J maxillula K maxilliped.

Figure 3. Bambalocra intwala sp. nov. Female paratype, 23.0 mm (SAMC-A 091365) A-E pleopods 1 - 5 respectively F pereopod 1 G pereopod 2 H pereopod 6 I pereopod 7.

Figure 4. Bambalocra intwala sp. nov. Male paratype, 7.5 mm (SAMC-A 091365) A dorsal view B frons C maxillula D mandible E antennula F antenna G maxilla apex H maxilliped I lateral view J head, dorsal view K pleotelson and uropods.

Figure 5. Bambalocra intwala sp. nov. Male paratype, 7.5 mm (SAMC-A 091365) A-E pleopods 1 - 5 respectively F pereopod 1 G pereopod 2 H pereopod 6 I pereopod 7.