Cymothoa propria Avdeev, 1979

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2016, Review of the fish-parasitic genus Cymothoa Fabricius, 1793 (Crustacea: Isopoda: Cymothoidae) from Australia, Zootaxa 4119 (1), pp. 1-72 : 32-36

Cymothoa propria Avdeev, 1979

Figures 18–21

Cymothoa propria Avdeev, 1979b: 50 , pl. 1, 2. — Trilles, 1994: 147. — Bruce, Lew Ton & Poore, 2002: 176. — Trilles & Bariche, 2006: 228.

Material examined. Paratypes: 2 ovig. ♀ (15, 20 mm), collected from northern Australia, on yellow-stripe scad Selaroides leptolepis (Cuvier, 1833) ( TINRO АPK 75002–75005).

Note: The female holotype ( TINRO AGK 75001) and male paratypes ( TINRO APK 75006–75008) could not be located, and our illustrations are based on female paratypes.

Ovigerous female Length 20 mm width 8 mm (paratype).

Body rhomboid, 2.1 times as long as greatest width, dorsal surface smooth, widest at pereonite 5 and 6. Cephalon subtriangular, 1.1 times longer than wide, slightly visible from dorsal view, not immersed in pereonite 1.

Frontal margin rounded to form blunt rostrum, ventrally folded. Eyes partially distinct. Pereonite 1 anterolateral margins minute, reaching posterior margins of eyes; posterior margins of pereonites 3–6 irregular; pereonites 5–7 subequal in length, posterolateral margins arched. Coxae 2–7 posteroventral margins rounded. Pleonites subequal in width, visible in dorsal view, pleonites posterior margins irregular. Pleotelson 0.5 times as long as anterior width, anterior margin irregular, lateral margins weakly concave, posterior margin subtruncate, without median point.

Antennula comprised of 8 articles; peduncle articles 1 and 2 distinct and articulated; article 2 1.3 times as long as article 1; article 3 0.8 times as long as combined lengths of articles 1 and 2, 1.2 times as long as wide. Antenna comprised of 7 articles, peduncle article 3 1.4 times as long as article 2, 1.8 times as long as wide; article 4 1.2 times as long as wide; article 5 0.9 times as long as article 4, terminal article without setae, not extending to posterior of pereonite 1.

Pereopod 1 basis 1.1 times as long as greatest width, superior proximal margin smooth, with moderately raised carina; ischium 0.6 times as long as basis; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus 1.0 times as long as wide; dactylus narrow, 1.6 times as long as propodus, 2.4 times as long as basal width. Pereopod 2 basis 1.4 times as long as greatest width, superior proximal margin smooth, without raised carina; propodus 1.3 times as long as wide; dactylus 1.5 times as long as propodus. Pereopods 3–5 similar to pereopod 2, gradually increasing in size, without robust or simple setae. Pereopod 6 basis 1.0 times as long as greatest width, superior proximal margin smooth, without raised carina; ischium 0.7 times as long as basis, inferior distal margin with slight protrusion; propodus 0.9 times as long as wide, dactylus 2.0 times as long as propodus. Pereopod 7 basis 0.9 times as long as greatest width, superior proximal margin smooth, with raised carina; ischium 0.7 times as long as basis, with bulbous protrusion; merus proximal margin with slight bulbous protrusion, 2.9 times as long as ischium, 2.0 times as long as wide; carpus 0.2 times as long as ischium, with slight bulbous protrusion, 0.4 times as long as wide; propodus 0.5 times as long as ischium, 1.0 times as long as wide; dactylus stout, 2.0 times as long as propodus, 2.5 times as long as basal width.

Uropod not extending beyond posterior margin of pleotelson; peduncle 2.2 times as long as greatest width, 0.7 times as long as exopod, lateral margin without setae, marginal setae absent, lateral margin straight, mesial margin straight. Exopod extending past endopod, 6.0 times as long as greatest width, apically rounded, lateral margin straight, terminating without setae, mesial margin weakly straight. Endopod 2.8 times as long as greatest width, apices narrowly acute, lateral margin weakly convex, terminating without setae, mesial margin straight.

Colour. Chestnut brown.

Remarks. Cymothoa propria has a rhomboid body that is widest at pereonites 5 and 6, pereonites 5–7 subequal in length; cephalon subtriangular and weakly immersed in pereonite 1; anterolateral margins on pereonite 1 minute; pleonites subequal in width; pleotelson posterior margin subtruncate, 2.2 times wider than long; uropodal rami reaching posterior margin of pleotelson; pereopod 7 ischium inferior distal margin with bulbous protrusion and superior proximal basis of pereopod 7 with raised carina. Avdeev’s (1979b) illustration of the female holotype included a simple maxillula, with 3 terminal setae; maxilla with 8 and 3 recurved setae on mesial lobe and lateral lobe respectively; maxilliped weakly segmented, terminal article 3 with five recurved setae; pleopod 1 exopod and endopod subequal in size; endopod mesial and distal margin straight, with deeply convex lateral margins, and proximal margins not extending beyond peduncle. Avdeev’s (1979b) male illustration differs from the female by having visible eyes, subequal pereonite length, minute anterolateral margins of pereonite 1, rounded posterior margin of pleotelson and appendix masculina present on pleopod 2.

Cymothoa propria resembles C. indica and C. plebeia Schioedte & Meinert, 1884 in the subtriangular cephalon and pleonites subequal in width. Cymothoa propria differs from both of those species in having a highly raised carina on pereopod 7 basis, 1.1 times wider than long (compared to the 0.9 times wider than long basis in C. indica and C. plebeia ); pereopod 7 dactylus extending almost to the distal margin of carpus (compared to dactylus of C. indica and C. plebeia that does not extend to distal margin of carpus) and the ventrally folded frontal lamina, appearing to immerse the paired antennae.

Distribution. Northern Australia ( Avdeev 1979b).

Hosts. Only known from Carangidae : Selaroides leptolepis (see Avdeev 1979b).

Figures

FIGURE 18. Cymothoa propria, ovigerous female paratype (20 mm; 75002 - 75005). A, dorsal view; B, front view of pereonite 1 and cephalon; C, dorsal view of pleotelson; D, lateral view.

FIGURE 19. Cymothoa propria, ovigerous female paratype (20 mm; 75002 - 75005). A, antennula; B, antenna; C, uropod; D – G, pereopods 1, 2, 6, 7 respectively.

FIGURE 20. Cymothoa propria, ovigerous female paratype (15 mm; APK 75002 - 75005). A, dorsal view; B, front view of pereonite 1 and cephalon; C, ventral view of mouthpart and pereopod 1 (dactylus and propodus); D, lateral view.

FIGURE 21. Cymothoa propria, ovigerous female paratype (15 mm; APK 75002 - 75005). A – E, pereopods 1, 2, 3, 6, 7 respectively.