Ceratothoa retusa (Schioedte & Meinert, 1883)

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2015, Review of the fish-parasitic genus Ceratothoa Dana, 1852 (Crustacea: Isopoda: Cymothoidae) from Australia, with description of two new species, Zootaxa 3963 (3), pp. 251-294 : 282

Ceratothoa retusa (Schioedte & Meinert, 1883)

Ceratothoae retusae Schioedte & Meinert in Hilgendorf, 1879: 847 [nomen nudum].

Cteatessa retusa .—Schioedte & Meinert, 1883: 297, tab. XI (Cym. XVIII) figs. 11–13.— Stebbing, 1908 – 1910: 424.— Barnard, 1924 –1926: 393; 1940: 491.— Nierstrasz, 1931: 131.— Trilles, 1986: 625, tab. 1; 1994: 130; 2008: 23.— Kensley, 1978: 79, figs. 32 (g–h).

Codonophilus hemiramphi Pillai, 1954: 14 –15 [nomen dubium].

Ceratothoa hemiramphi .— Trilles, 1994: 120.— Kensley, 2001: 232.

Ceratothoa retusa .— Bruce & Bowman, 1989: 8, figs. 5–8.— Kensley, 2001: 232.— Bruce, Lew Ton & Poore, 2002: 173.— Trilles, Ravichandran & Rameshkumar, 2011: 446.— Hadfield, 2012: 161, figs. 4.37–4.38.— Hadfield, Bruce & Smit, 2014a: 5 .—Smit, Bruce & Hadfield, 2014: 6, figs. 3(I).— Hadfield, Bruce, Szinetár & Smit, 2014b: 448 , figs. 1–8.

Type and type locality. The lectotype, designated by Hadfield et al. (2014b) is held at the Swedish Museum of Natural History ( SMNH 8579), collected by Wahlberg near Port Natal, South Africa from an unknown host and figured by Schioedte & Meinert (1883). Paralectotypes include one ovigerous female held at the Swedish Museum of Natural History ( SMNH 8324) collected near Port Natal, South Africa by Wahlberg from an unknown host and one non-ovigerous female held at the Zoological Museum ( ZMHB 1708) collected from Mozambique by W. Peters from an unknown host ( Hadfield et al. 2014b).

Remarks. Ceratothoa retusa is readily identified by the large anterolateral projections of pereonite 1, rectangular-shaped body, dorsally visible coxae, with coxae 4–7 with posteriorly acute projections, posterior margin of pleotelson subtruncate, and pereopods 5–7 with posteriorly expanded basis. Bruce & Bowman (1989) and Hadfield et al. (2014b) provided recent reviews and noted variation of C. retusa specimens from Indonesia, South Africa, West Irian, Red Sea and Australia. Hadfield et al. (2014b) listed nine varying characters observed between different C. retusa specimens from different regions of the Indian Ocean. The species has only been recorded from half-beaks, Hemirhamphus spp.

Ceratothoa hemiramphi Pillai, 1954 is placed into nomen dubium because the original description lacks sufficient information and there were no figures. This species is similar to C. retusa on the basis of Pillai’s (1954) brief account describing the prominent anterolateral projections on pereonite 1 that extend beyond the eyes, along with the host identity.

Hilgendorf (1879) referred to the species “ Ceratothoae retusae” collected by Peters from Mozambique without type allocation or description. “ Ceratothoae retusae” was placed into nomen nudum by Bruce & Bowman (1989) and Schioedte & Meinert (1883) became the authorities for the species.

Distribution. Northern Australia and Western Irian Jaya ( Bruce & Bowman 1989); Indonesia (Trilles 2008); India ( Pillai 1954; Bruce & Bowman 1989; Trilles et al. 2011); South Africa (Schioedte & Meinert 1883; Stebbing 1908 – 1910; Barnard 1924 –1926; 1940; Bruce & Bowman 1989); Mozambique ( Nierstrasz 1931; Bruce & Bowman 1989); Red Sea ( Hadfield et al. 2014b).

Hosts. Halfbeak fish Hemirhamphus far (Forsskål, 1775) ( Barnard 1924 –1926; Pillai 1954; Kensley 1978; Bruce & Bowman 1989; Hadfield et al. 2014b); Hemirhamphus robustus Günther, 1866 ( Bruce & Bowman 1989; Hadfield et al. 2014b).