Smenispa irregularis ( Bleeker, 1857 )

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2014, Smenispa irregularis (Bleeker, 1857) (Crustacea: Isopoda: Cymothoidae), a Buccal-attaching Fish Parasite from Australia, Records of the Australian Museum 66 (4), pp. 233-240 : 235-236

Smenispa irregularis ( Bleeker, 1857)

Figs 1–5

Cymothoa irregularis Bleeker, 1857: 34 , pl. 2, figs. II.— Miers, 1880: 462.— Gerstaecker, 1882: 261.

Cymothoa paradoxa Haller, 1880: 378 , pl. 18, figs. 5–7.— Gerstaecker, 1882: 261.

Enispa irregularis .—Schioedte & Meinert, 1884: 293, pl. 11, figs. 1–4.— Nierstrasz, 1915: 95.— Nierstrasz, 1931: 137.— Trilles, 1979:259, pl. 1, figs. 6; 1994: 152.— Bruce, 1990: 282, figs. 24–25.

Type material. SYNTYPES 2 ♀ (ovigerous 19 mm, 23 mm), Rijksmuseum van Natuurlijke Historie ( RMNH 62 ), “Oost Indie”, coll. P. Bleeker (not examined) .

Material examined. Western Australia: 1 ♀ (24 mm, ovig., damaged pleonite, mouthpart and pereopods) , 1 ♂ (9 mm), AM P89833, from Carnarvon, 24°53'S 113°40'E, 1982, from buccal cavitY of Yellowfin seabream Acanthopagrus latus (Houttuyn, 1782) .

Diagnosis. Female. Cephalon embedded in pereonite 1. Pereonite 1 anterior margin trilobed; lateral margins of pereonites subparallel, pereonites 1 and 2 arching anteriorly, pereonite 2 posterolateral margins produced, lateral margins of pleonites subparallel and arching posteriorly, pleotelson subtruncate and endopod larger than exopod. Male. BodY similar to female; cephalon dorsallY visible; pleon width 0.6 pereonite greatest width; pleopod 2 appendix masculina slender, apex distally acute, length 0.8 endopod length, not reaching beYond exopod; pleopod 2 endopod length 1.9 width, medial margin produced, slightlY extending exopod; exopod length 1.5 width, proximal lateral margin stronglY produced.

Description. Female. Body length 2.0 greatest width, dorsal surface smooth appearance, widest at pereonite 5, most narrow at pereonite 1. Cephalon length 1.0 width, visible from dorsal view, embedded in pereonite 1; frontal margin ventrally folded. Eyes indistinct, eYe width 0.1 width of cephalon. Antennula shorter than antenna, comprised of 8 articles; article 2 length 2.0 article 1 length; not extending to posterior margin of eye. Antenna comprised of 12 articles, last article terminating without setae.

Pereonite margins smooth, increasing in width from pereonites 1–5, pereonite 1 length 0.3 width, anterolateral margin produced, extending past cephalon; pereonite 5 widest, length 0.2 width; pereonite 6 and 7 lateral parts with posteriorlY produced lobes. Coxae 2–3 posteroventral angles produced; 4–7 not acute posteriorlY, with oblique carina. Pleonites visible in dorsal view; lateral margins arching posteriorly. Pleonite 1 posterolateral angles not hidden behind pleonite 2; pleonites 1–5 subparallel. Pleotelson length 0.5 anterior width, dorsal surface smooth, anterolateral margins weaklY convex, posterior margin straight, without median point.

Pereopods 1–7 dactYlus narrowlY curved, merus and carpus of similar length, not produced. Pereopod 1 basis length 1.8 greatest width; ischium length 0.6 basis length; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus length 1.3 width. Pereopods 2 and 3 similar to pereopod 1, gradually increasing in size. Pereopod 6 basis length 2.0 greatest width, ischium length 0.4 basis length. Pereopod 7 basis length 1.6 greatest width; ischium length 0.6 basis length, merus length 0.4 ischium length, merus length 0.7 width; carpus length 0.1 ischium length, carpus length 0.3 width.

Pleopods (damaged), without setae. Uropod half the length of pleotelson, protopod length 0.8 endopod, protopod lateral margin without setae; rami not extending beYond pleotelson, apices bluntly rounded. Endopod apically not bifid, length 3.0 greatest width, lateral margin proximally convex, distally concave. Exopod shorter than endopod, length 2.8 greatest width, apicallY not bifid, terminates without setae.

Male. BodY subparallel, length 2.2 width. Cephalon length 1.5 width, visible from dorsal view, not embedded in pereonite 1. Eyes distinct and well developed. Pereonites without posterior lateral lobes, similar in length. Antennula comprised of 8 articles. Antenna comprised of 10 articles, last article terminating without setae, extending to posterior of pereonite 1.Anterior margin of cephalon subtruncate, without small median point. Mandibular process present, covered in pectinate scales, article 3 with fine setae. Maxillula with 3 narrow spines. Maxilla mesial lobe with 2 recurved spines, partlY fused to lateral lobe with 2 recurved spines. Maxilliped article 3 with 2 recurved robust setae. Lateral ends of pleonites less developed than in female. Pereopods 1–7 similar to female; dactYlus length 0.8 basis length.

Pleopods without setae, without lobes on pleopods 1–2. Pleopod 1 exopod length 1.3 width, lateral margin weaklY convex, mesial margin weaklY produced; endopod length 1.7 width, lateral margin straight, mesial margin slightlY convex; protopod width 4.0 length. Pleopod 2 endopod length 1.9 width, medial margin produced, slightlY extending exopod; exopod length 1.5 width, proximal lateral margin stronglY produced; appendix masculina slender, apex distally acute, length 0.8 endopod length, not reaching beyond exopod. Pleopods 2–5 with basal projections; exopods proximal lateral border extending beYond protopod; endopods proximal mesial boarder extending past protopod boarder, endopod dorsal with large medial fleshY folds. Uropods dorsally visible, slightly hidden by pleotelson.

Colour. Present specimens (female and male) dark orange brown. Bruce (1990) reported pale tan in the Northern TerritorY specimen with no chromatophores present.

Size. Non-ovigerous female 24 mm, male 9 mm. Other reports include Bleeker (1857) (female: 28 mm), Schioedte & Meinert

(1884) (ovigerous female: 20–24 mm non ovigerous female 22 mm; male 5–8 mm), Haller (1880) (ovigerous female: 18 mm), Trilles (1979) (ovigerous female: 19 mm; males 16 mm).

Figures

Figure 1. World map of the distribution of Smenispa irregularis (circles) and Smenispa convexa (stars).

Figure 2. Smenispa irregularis, ovigerous female (24 mm) (AM P89833). (A) dorsal view of bodY; (B) lateral view of bodY; (C) front view of pereonite 1 and cephalon; (D) antennula; (E) antenna; (F) pereopod 1; (G) pereopod 2; (H) pereopod 6; (I) uropod; (J) pereopod 7; (K) dorsal view of pleotelson; (L) ventral view of pleotelson. Scales = 2 mm, except D, E = 0.5 mm.

Figure 3. Smenispa irregularis, male (9 mm) (AM P89833).(A) dorsal view of bodY; (B) lateral view of bodY; (C) antennula; (D) antenna; (E) mandible; (F) maxillula; (G) maxilliped; (H) maxilla. Scales:A, B= 1 mm; C, D = 0.5 mm; E–H = 0.25 mm.

Figure 4. Smenispa irregularis, male (9 mm) (AM P89833). (A–D) pereopod 1, 2, 6, 7 respectivelY; (E) ventral view of pleotelson. Scales: A–D= 0.25 mm; E = 1 mm.

Figure 5. Smenispa irregularis, male (9 mm) (AM P89833). (A–E) pleopod 1–5 respectivelY. Scales = 0.25 mm.