Ceratothoa famosa, Hadfield, Kerry A., Bruce, Niel L. & Smit, Nico J., 2014

Hadfield, Kerry A., Bruce, Niel L. & Smit, Nico J., 2014, Review of the fish parasitic genus Ceratothoa Dana, 1852 (Crustacea, Isopoda, Cymothoidae) from South Africa, including the description of two new species, ZooKeys 400, pp. 1-42 : 7-10

Ceratothoa famosa sp. n. Figs 8-14, 21

Meinertia imbricata ?.- Trilles 1972: 1248-1250, pl. II (10-11).

Material examined.

Holotype. Female (23 mm TL; 10 mm W), collected from Tsitsikamma National Park (34°1'S, 23°52'E) along the south coast of South Africa from the buccal-cavity of Diplodus sargus capensis , March 2005, coll. K.A. Hadfield (SAM A45939).

Paratypes. All from Tsitsikamma National Park (34°1'S, 23°52'E), Western Cape Province. From the buccal-cavity of Diplodus sargus capensis : dissected female (27 mm TL; 12 mm W), dissected male (13 mm TL; 6 mm W), April 2009, coll. K.A. Hadfield (SAM A45940); female (17 mm TL; 7 mm W), males (7, 14 mm TL; 3, 6 mm W), March 2005, coll. K.A. Hadfield (SAM A45941).

From the buccal-cavity of Sparadon durbanensis : female (15 mm TL; 6 W), male (5.5 mm TL; 2 mm W), April 2009, coll. K.A. Hadfield (SAM A45942).

Other material. In the possession of authors at NWU. From Diplodus sargus capensis : Cape Agulhas (34°49'S, 20°0'E): female (18 mm TL; 7 mm W), male (9 mm TL; 3 mm W). Kenton-on-sea (33°42'S, 26°41'E): female (14 mm TL; 5 mm W), male (5 mm TL; 2 mm W), May 1974. Morgan Bay (32°42'S, 28°20'E): two females (10, 12 mm TL; 3, 4 mm W), April 2003. Swartkops River Estuary (33°52'S, 25°38'E): female (10 mm TL; 3 mm W), male (6 mm TL; 2 mm W), July 1980. Transkei, between Goss Bay and Lupatana: female (10 mm TL; 4 mm W), September 1975. Transkei, Grosvenor Point (31°22'S, 29°53'E): female (15 mm TL; 6 mm W), male (6 mm TL; 2 mm W), September 1975. Tshani (31°56'S, 29°12'E): female (10 mm TL; 3 mm W), June 1996.

From Diplodus cervinus hottentotus : Kleinemonde (33°32'S, 27°03'E): female (25 mm TL; 6 mm W), male (5 mm TL; 2 mm W), June 1975; female (15 mm TL; 6 mm W), male (6 mm TL; 2 mm W), March 1975; Keiskamma River Mouth (33°16'S, 27°29'E): female (18 mm TL; 8 mm W), male (9 mm TL; 4 mm W), February 1976; Knysna (34°5'S, 23°3'E): female (19 mm TL; 7 mm W), male (8 mm TL; 3 mm W), 1945-1969. Tsitsikamma National Park (34°1'S, 23°52'E): female (20 mm TL; 7 W), male (14 mm TL; 5 mm W), 17 juveniles, March 2007.

From Sparadon durbanensis : Cape Padrone, Eastern Cape (33°46'S, 26°28'E): four pullus (5 mm TL; 2 mm W), July 1975. Kleinemonde (33°32'S, 27°03'E): five pullus (4 mm TL; 2 mm W), February 1977. Knysna (34°5'S, 23°3'E): two pullus (5 mm TL; 2 mm W), 1945-1965. Tsitsikamma National Park (34°1'S, 23°52'E): female (26 mm TL; 12 W), male (12 mm TL; 5 mm W), 35 juveniles, July 2008.

Ovigerous female holotype.

Length 10-28 (16.9) mm, width 3-12 (6.0) mm.

Body rectangular, 1.7 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 4 and pereonite 5, most narrow at pereonite 7, lateral margins slightly convex. Cephalon 0.8 times longer than wide, slightly visible in dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes irregular in outline. Pereonite 1 with median projection, anterior border straight, anterolateral angle with distinct anterior projection, posterior margins of pereonites smooth and slightly curved laterally. Coxae 2-3 with posteroventral angles not visible; 4-7 rounded. Pereonites 1-5 increasing in length and width; 6-7 decreasing in length and width; becoming more progressively rounded posteriorly. Pleon with pleonite 1 same width as other pleonites, visible in dorsal view; pleonites posterior margin smooth, mostly concave; posterolateral angles of pleonite 2 narrowly rounded, not posteriorly produced. Pleonites 3-5 similar in form to pleonite 2. Pleonite 5 with posterolateral angles free, not overlapped by lateral margins of pleonite 4, posterior margin with 2 indented points and medial indent. Pleotelson 0.5 times as long as anterior width, dorsal surface smooth, lateral margins posteriorly narrow, posterior margin broadly truncate, without median point.

Antennule more stout than antenna, comprised of 7 articles; peduncle articles 1 and 2 distinct and articulated; article 2 0.8 times as long as article 1; article 3 0.3 times as long as combined lengths of articles 1 and 2, 0.8 times as long as wide; flagellum with 4 articles, extending to anterior of pereonite 1. Antenna comprised of 9 articles. Antenna peduncle article 3 1.4 times as long as article 2, 1.1 times as long as wide; article 4 1.1 times as long as wide, 0.9 times as long as article 3; article 5 0.5 times as long as article 4, 0.8 times as long as wide. Antenna flagellum with 4 articles, last article terminating in no setae, extending to anterior margin of pereonite 1. Anterior margin rounded, forming median point. Mandibular process ending in an acute incisor, with no simple setae, mandible palp article 2 with no distolateral setae, and article 3 with 7 serrate setae. Maxillule simple with 4 terminal robust setae. Maxilla mesial lobe partly fused to lateral lobe; lateral lobe with no simple setae, 6 recurved robust setae; mesial lobe with no simple setae, and 4 large recurved robust setae. Maxilliped weakly segmented, with lamellar oostegite lobe, palp article 2 with no simple setae, article 3 with 3 recurved robust setae, and no simple setae. Oostegites margin covered in numerous plumose setae, attached to pereopods 2-5.

Pereopod 1 basis 1.6 times as long as greatest width; ischium 0.8 times as long as basis; merus proximal margin with bulbous protrusion; carpus with straight proximal margin; propodus 1.4 times as long as wide; dactylus slender, 1.1 as long as propodus, 2.5 times as long as basal width. Pereopod 2 propodus 1.5 as long as wide; dactylus 1.1 as long as propodus. Pereopods gradually increasing in size towards posterior and all without robust or simple setae. Pereopod 6 basis 1.6 times as long as greatest width, ischium 0.8 times as long as basis, propodus 1.5 as long as wide, dactylus 1.2 as long as propodus. Pereopod 7 basis 1.3 times as long as greatest width; ischium 0.9 as long as basis, without protrusions; merus proximal margin with slight bulbous protrusion, merus 0.3 as long as ischium, 0.5 times as long as wide; carpus 1 as long as ischium, without bulbous protrusion, 0.7 times as long as wide; propodus 2.1 as long as ischium, 1.4 times as long as wide; dactylus slender, 1.3 as long as propodus, 2.9 times as long as basal width.

Pleopods without setae, exopod larger than endopod. Pleopod 1 exopod 1.1 times as long as wide, lateral margin weakly convex, distally broadly rounded, mesial margin straight; endopod 1.4 times as long as wide, lateral margin convex, distally subtruncate, mesial margin straight; peduncle 3.3 times as wide as long, without retinaculae. Pleopods 2-5 similar to pleopod 1. Pleopods 3-5 endopods proximal borders do not extend below exopod to peduncle. Large medial lobes absent.

Uropod same length as pleotelson, peduncle 1 times longer than rami, peduncle lateral margin without setae; rami extending to pleotelson apex, marginal setae absent, apices narrowly rounded. Endopod apically slightly pointed, 4.1 times as long as greatest width, lateral margin straight, terminating without setae, mesial margin straight. Exopod extending to end of endopod, 3.3 times as long as greatest width, apically rounded, lateral margin weakly convex, terminating with no setae, mesial margin straight.

Male.

Length 4-14 (8.2) mm, width 1-5 (3.3) mm.

Males similar to females but much smaller. Body rectangular, 1.6 times as long as wide. Penis small, low tubercles. Pleopod 2 appendix masculina absent.

Etymology.

A photograph by one of us (NJS) of this species in the mouth of a Diplodus sargus capensis from Tsitsikamma National park, posted on the internet in 2004 has been used in many media reports worldwide, including magazines, children’s books, documentaries, nature programmes, daily news reports, and even in a motion picture. The epithet is derived from famosus (Latin-famous) ( Brown 1956).

Distribution.

Known from off the southern coast of South Africa: Cape Agulhas; Knysna; Tsitsikamma; Swartkops River Estuary; Kenton-on-sea; Kleinemonde; Keiskamma River Mouth; Morgan Bay; Tshani; Grosvenor Point; and Transkei (between Goss Bay and Lupatana).

Hosts.

Found on the tongue of Diplodus sargus capensis (Smith, 1844), Diplodus cervinus hottentotus (Smith, 1844) and Sparadon durbanensis (Castelnau, 1861).

Prevalence.

1/3 (33.3%) of Diplodus cervinus hottentotus , 6/20 (30%) of Diplodus sargus capensis and 6/33 (18.2%) of Sparadon durbanensis infected from Tsitsikamma National Park; 26/366 (7.1%) of Diplodus cervinus hottentotus , 78/1004 (7.8%) of Diplodus sargus capensis and 11/100 (11%) of Sparadon durbanensis from the SAIAB collections.

Remarks.

Ceratothoa famosa sp. n. can be distinguished by the long rectangular body shape, pereonite 1 with a raised medial protrusion, a blunt rostrum, narrow antenna with antennule article 1 expanded, uropods which reach the posterior margin of the pleotelson, pereopods 1 and 2 with large bulbous protrusion on merus, narrow rami on uropods, and no appendix masculina on pleopod 2 of the male specimens.

Ceratothoa famosa sp. n. is similar to Ceratothoa trigonocephala in having pereonites 1-4 almost subequal but has a more bluntly rounded anterior margin of the cephalon observed in Ceratothoa imbricata as well as the two mediolateral concave indents in pleonite 5. Specific characters for Ceratothoa famosa include an antennule with an enlarged first article; a medial protrusion on pereonite 1 creating a rounded elevation around the cephalon; and a rostral point which is folded over between the antennae. The anterolateral margins are close to the cephalon and are bluntly rounded extending just past the middle of the cephalon. The uropods are the same length as the pleotelson and the male specimens lack an appendix masculina on pleopod 2 as seen with Ceratothoa oestroides (Risso, 1826), Ceratothoa italica Schioedte & Meinert, 1883, Ceratothoa capri (Trilles, 1964c), Ceratothoa gilberti (Richardson, 1904) and Cymothoa gaudichaudii . The pleopods do not have many folds or lobes but the pereopods have large carinae and extended protrusions on the merus of pereopods 1 and 2.

Other differences between Ceratothoa famosa sp. n. and Ceratothoa africanae sp. n. is the rostral point, which is blunt and ventrally directed and does not fold over in Ceratothoa africanae .; Ceratothoa famosa pereonite 7 overlaps pleonite 1 and the P1-P4 merus has a large bulbous protrusion which is smaller in P5-P7 (opposite in Ceratothoa africanae sp. n.); and Ceratothoa famosa . has pointed rather than rounded anterolateral margins on pereonite 1 as seen in Ceratothoa africanae .

Miers (1876) commented that South African specimens in his possession from the Cape of Good Hope did not correspond to the specimens of Ceratothoa imbricata in the British Museum and that there was a probability that the specimens were a distinct species. It is probable that all the records of Ceratothoa imbricata (or Ceratothoa banksii Leach, 1818) from South Africa are Ceratothoa famosa sp. n.