Ceratothoa angulata ( Richardson, 1910 )

Ravichandran, S., Vigneshwaran, P. & Rameshkumar, G., 2019, A taxonomic review of the fish parasitic isopod family Cymothoidae Leach, 1818 (Crustacea: Isopoda: Cymothooidea) of India, Zootaxa 4622 (1), pp. 1-99 : 16-17

Ceratothoa angulata ( Richardson, 1910)

( Fig. 1 g–i)

Meinertia angulata Richardson, 1910: 22 , fig. 21 .

Codonophilus angulatus .— Nierstrasz, 1931: 132.

Ceratothoa angulata .— Bruce & Bowman 1989: 2–4, figs 1, 2.— Trilles, 1994: 116.—Williams, Bunkley-Williams & Pitlik 2000: 157–158.—Paulay, Kropp, Ng & Eldredge, 2003: 479.— Rameshkumar, Ravichandran & Sivasubramanian, 2013: 99–105.— Hadfield, Bruce & Smit, 2016: 42–45, fig. 1.

Not Ceratothoa angulata . — Ravichandran, Rameshkumar & Trilles, 2011: 232–234, fig. 1a. [ Glossobius auritus ].

Type and type locality. The holotype female (21 mm TL; 8 mm W) Meinertia angulata , held at United States National Museum, USA ( USNM 41008) from Port San Pio, Philippines, near mouth of a small stream, host unknown, 11 Nov 1908 ( Richardson 1910).

Material examined. 2 ovig. females (25, 29 mm) ( CAS / MBRM C- 105– C- 106), June 2010, and 1 ovig. female (26 mm) ( ZSI / MBRC D1-534). All from Hyporhamphus dussumieri (Valenciennes, 1847) , Parangipettai, the Southeastern coast of India. coll. S. Ravichandran.

Remarks. Ceratothoa angulata can be identified by the truncate anterolateral margins of pereonite 1 which form distinct ridges on lateral sides and two small medial depressions, the slightly emarginate and truncate pleotelson, and the broadly rounded uropodal exopod.

Richardson’s (1910) description was based on a single specimen, a female from an unidentified host in the Philippines, and consisted of a short description with a single figure. Bruce & Bowman (1989) provided a redescription based on the holotype (with only two figures) and additional material from Borneo (a non ovig. female and male), including a short description of the male and figures for both specimens. The holotype (USNM 41008) was recently redescribed and detail figured by Hadfield et al. (2016). Ceratothoa angulata resembles Ceratothoa guttata ( Richardson, 1910) with the narrow pleon and pleotelson but the unique pereonite 1 makes it readily distinguishable from other species.

Ravichandran et al. (2011) reported Ceratothoa angulata ( Richardson, 1910) from the host Hyporhamphus dussumieri (Valenciennes, 1847) is a misidentification and refers to Glossobius auritus Bovallius, 1885 : other characters are discussed under Remarks for G. auritus to which this species is similar.

Colour. Ivory white to pale brown in alcohol.

Size. Ovig. females (17.5– 29 mm), non ovig. females (18–26 mm); male (7 mm) ( Bruce & Bowman 1989; Williams et al. 2000).

Distribution. Ceratothoa angulata distributed from the western and central Indo–Pacific region: Philippines ( Richardson 1910), Indonesia ( Nierstrasz 1931; Bruce & Bowman 1989), Guam, Micronesia ( Williams et al. 2000) and India ( Rameshkumar et al. 2013).

Hosts. Known only from family Hemiramphidae : Dussumier’s halfbeak, Hyporhamphus dussumieri (previously H. laticeps ) ( Bruce & Bowman 1989; Williams et al. 2000).

Figures

FIGURE 1. a–c, Anilocra dimidiata Bleeker, 1857, female (24 mm), (ZSI/MBRC D1-529); d–f, Catoessa boscii (Bleeker, 1857), female (17 mm), (ZSI/MBRC D1-530); g–i, Ceratothoa angulata (Richardson, 1910), female (29 mm), (ZSI/MBRC D1-533); j–l, Cymothoa bychowskyi Avdeev, 1979, female (27 mm), (CAS/MBRM C-87); m–o, Cymothoa eremita (Brünnich, 1783), female (29 mm), (ZSI/MBRC D1-532); p–r, Cymothoa frontalis Milne Edwards, 1840, female (25 mm), (CAS/MBRM C-89).

FIGURE 21. Ryukyua globosa Williams & Bunkley-Williams, 1994, female (14 mm), (ZSI/MBRC D1-552). a, mandible; b, maxilla; c, maxillula; g, maxilliped; e–h, pereopod 1, 2, 4 & 5.