Ceratothoa retusa
Creators: name: Ravichandran, S.
name: Vigneshwaran, P.
name: Rameshkumar, G.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Cymothoidae
Ceratothoa
Ceratothoa retusa

description: Ceratothoa retusa (Schiöedte & Meinert, 1883)
Ceratothoae retusae Schiöedte & Meinert in Hilgendorf, 1879: 847 [nomen nudum].
Cteatessa retusa.— Schiöedte & 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, fig. 32g–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, fig. 3i.— Hadfield, Bruce, Szinetár & Smit, 2014b: 448, figs 1–8.— Martin, Bruce & Nowak, 2015a: 282.
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 Schiöedte & Meinert (1883). Paralectotypes include one ovig. 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 ovig. 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.
Pillai’s (1954) preliminary diagnosis of Codonophilus hemiramphi was brief, and no illustrations accompanied it a later report (Pillai, 1964) gave full descriptions and illustrations of three of the isopods diagnosed in 1954, but did not include C. hemiramphi therefore, Ceratothoa hemiramphi (Pillai, 1954) is placed into nomen dubium. His diagnosis (Pillai 1954:15) of C. hemiramphi was based largely on pereonite 1: “The anterior half of the lateral border is very prominently ridge like and a little internal to this is another equally prominent dorsal ridge. The space in between these two ridges is flat or even slightly concave giving it the appearance of an independent facet”. If his dorsal ridge is the continuation of the lateral ridge medially onto the dorsal surface of pereonite 1, this description similar with C. retusa (Bruce & Bowman 1989).
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 Schiöedte & Meinert (1883) became the authorities for the species.
Distribution. The species has been recorded from the Indian Ocean to west Pacific Ocean. Indian Ocean: Indonesia (Trilles 2008), India (Pillai 1954; Bruce & Bowman 1989; Trilles et al. 2011), South Africa (Schiöedte & Meinert 1883; Stebbing 1908–1910; Barnard 1924–1926; 1940; Bruce & Bowman 1989), Mozambique (Nierstrasz 1931; Bruce & Bowman 1989) and Red Sea (Hadfield et al. 2014b). Pacific Ocean: Northern Australia and Western Irian Jaya (Bruce & Bowman 1989).
Hosts. Known only from the family Hemiramphidae: Halfbeak fish Hemirhamphus far (Forsskål, 1775) (Barnard 1924–1926; Pillai 1954; Kensley 1978; Bruce & Bowman 1989; Hadfield et al. 2014b) and Hemirhamphus robustus Günther, 1866 (Bruce & Bowman 1989; Hadfield et al. 2014b).
description: Published as part of Ravichandran, S., Vigneshwaran, P. & Rameshkumar, G., 2019, A taxonomic review of the fish parasitic isopod family Cymothoidae Leach, 1818 (Crustacea: Isopoda: Cymothooidea) of India, pp. 1-99 in Zootaxa 4622 (1) on page 17, DOI: 10.11646/zootaxa.4622.1.1, http://zenodo.org/record/3379899