Review Article |
Corresponding author: Kerry A. Hadfield ( kerryh26@yahoo.com ) Academic editor: Paula Beatriz Araujo
© 2016 Kerry A. Hadfield, Niel L. Bruce, Nico J. Smit.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hadfield KA, Bruce NL, Smit NJ (2016) Redescription of poorly known species of Ceratothoa Dana, 1852 (Crustacea, Isopoda, Cymothoidae), based on original type material. ZooKeys 592: 1-53. https://doi.org/10.3897/zookeys.592.8098
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Due to the difficulty in accurately identifying cymothoids, these parasitic isopods are often incorrectly named or confused with other species. Within the genus Ceratothoa, a number of recent studies have aimed at clarifying some of the problematic species; however, several of the less studied species still require revision. This paper redescribes, from type material, several poorly known Ceratothoa species including C. angulata, C. capri, C. carinata, C. collaris, C. gilberti, C. gobii, C. guttata, C. italica, C. oestroides, and C. verrucosa, further resolving taxonomic uncertainties within the genus.
marine fish parasite, buccal-cavity, mouth, tongue-biter, tongue replacement, Isopoda , Cymothoidae , Ceratothoa
Although being one of the physically larger parasitic isopods, cymothoids are still relatively understudied. Often easily observed, these isopods can be located inside the gills, mouths, body cavities and on external surfaces of their fish hosts (
However, several cymothoid species have not been studied in many years. A number of factors could be responsible for this lack of research, including a lack of cymothoid specialists, but it is highly probable that many of these species cannot be accurately identified from the original descriptions. This paper revises these poorly known species of Ceratothoa Dana, 1852 with redescriptions based on their type material.
Currently there are 30 Ceratothoa species known worldwide (according to the World List of Marine, Freshwater and Terrestrial Isopod Crustaceans database (
Type material for the Ceratothoa species was borrowed where available or drawn at their respective museums. Isopods were processed according to the techniques described in
Abbreviations.
Ceratothoa
Dana, 1852: 303;
Codonophilus
Haswell, 1881: 471.—
Rhexana Schioedte & Meinert, 1883: 289–290.
Cteatessa Schioedte & Meinert, 1883: 296–297.
Meinertia
Stebbing, 1893: 354;
Rhexanella Stebbing, 1911: 179.
Not Ceratothoa.—
Cymothoa parallela Otto, 1828 (by subsequent designation, see
Diagnostic characters for Ceratothoa include the contiguous and swollen antennular bases, triangular cephalon, and the elongate body (2.1–2.9 times as long as wide). Ceratothoa also has a pleotelson and pleonite 1 which are narrower than the other pleonites, and subequal uropod rami which do not extend past the pleotelson. A full diagnosis of the genus is provided by
Meinertia angulata Richardson, 1910: 22, fig. 21.
Codonophilus
angulatus
.—
Ceratothoa
angulata
.—
Holotype. United States National Museum, USA (
Holotype female. Length 21 mm, width 8 mm.
Body oval, twice as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5, most narrow at pereonite 7, lateral margins posteriorly ovate. Cephalon 0.5 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins, one eye 0.3 times width of cephalon, 0.5 times length of cephalon. Antennula more stout but same length as antenna, same length as antenna, with 7 articles. Antenna with 7 articles; antennae extending to middle of the eye.
Pereonite 1 with a slight dorsomedial projection, anterior border straight, anterolateral angles extending to anterior margin of eyes with wide truncated and dorsally projected ridges, slight depression at base of each ridge. Posterior margins of pereonites smooth and straight, with posteroventral angles rounded. Coxae 4–7 rounded; not extending past pereonite margin. Pereonites 1–5 increasing in length and width, 6–7 decreasing in length and width, becoming more progressively rounded posteriorly. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin smooth, mostly concave; pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 posterior margin produced medially. Pleotelson 0.6 times as long as anterior width, dorsal surface smooth, lateral margins posteriorly narrow, posterior margin subtruncate and shallowly emarginate.
Pereopod 1 basis 1.6 times as long as greatest width; ischium 0.8 times as long as basis; merus proximal margin with bulbous protrusion; carpus with straight proximal margin; propodus 1.2 times as long as wide; dactylus slender, 1.5 as long as propodus, 3 times as long as basal width. Pereopod 7 basis 0.8 times as long as greatest width; ischium as long as basis, with a large proximal bulbous protrusion; merus proximal margin with large bulbous protrusion, merus 0.5 times as long as wide, 0.3 times as long as ischium; carpus 0.8 times as long as wide, 1.1 times as long as ischium, without bulbous protrusion; propodus 1.3 times as long as wide, 0.5 times as long as ischium; dactylus slender, 1.7 times as long as propodus, 3.3 times as long as basal width.
Uropod same length or slightly longer than the pleotelson; peduncle 1.3 times longer than rami, peduncle lateral margin without setae; rami subequal, extending beyond pleotelson, marginal setae absent. Endopod 2.6 times as long as greatest width, straight medial margin, convex lateral margin, apically slightly pointed; exopod 2.3 times as long as greatest width, extending to end of endopod, apically rounded.
Female: 17.5–21.5 mm TL (9 mm W); male: 7 mm TL (
Known from the western and central Indo-Pacific region: Philippines (
In the buccal cavity of Dussumier’s halfbeak, Hyporhamphus dussumieri (previously H. laticeps) (
The distinguishing characters of C. angulata include the truncate anterolateral margins of pereonite 1 which form distinct ridges on both lateral sides and two small medial depressions, the slightly emarginate and truncate pleotelson, and the broadly rounded uropodal exopod. The unusually large, quadrate pereonite 1 formed from the lateral ridges is very characteristic for this species.
Ceratothoa angulata resembles C. guttata with the narrow pleon and pleotelson but the unique pereonite 1 makes it readily distinguishable from other species.
Meinertia
capri
Trilles, 1964a: 188–198, figs 1–41;
Ceratothoa
capri
.—
Lectotype [here designated]. National Museum of Natural History, Paris (
Lectotype female. Length 16 mm, width 8 mm.
Body oval, 1.7 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5, most narrow at pereonite 1, lateral margins posteriorly ovate. Cephalon 0.5 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins, one eye 0.3 times width and length of cephalon. Antennula more stout than antenna. Antenna with 8 articles.
Pereonite 1 smooth, anterior border straight, anterolateral angle acute, anteriorly produced, extend to anterior margin of eyes. Posterior margins of pereonites smooth and slightly curved laterally. Coxae 2–3 narrow; 4–7 with rounded point; not extending past pereonite margin. Pereonites 1–5 increasing in length and width; 6–7 decreasing in length and width; 6 and 7 narrower and becoming more progressively rounded posteriorly. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin smooth, mostly concave. Posterolateral angles of pleonite 2 narrowly rounded.
Pereopod 1 basis 1.7 times as long as greatest width; ischium 0.8 times as long as basis; merus proximal margin with bulbous protrusion; carpus with straight proximal margin; propodus 1.6 times as long as wide; dactylus slender, 1.1 times as long as propodus, 2.9 times as long as basal width. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin produced medially. Pleotelson 0.6 times as long as anterior width, dorsal surface with 2 sub-medial depressions, lateral margins weakly convex, posterior margin subtruncate.
Female: 13–20 mm TL; male: 6–7 mm TL; second pullus: 2.5–3.5 mm TL (
Throughout the Mediterranean with records from France (
On the branchio-spines in the gill and on the bottom of the buccal cavity of Capros aper (see
Ceratothoa capri can be distinguished by the acute anterolateral margins which extend past the prominent eyes; body widest at pereonite 5; a narrow pleotelson; and no appendix masculina on the second pleopod in males.
There are a number of species of Ceratothoa in the Mediterranean; however C. capri differs from them all. There are several differences between C. capri and C. gobii but the most obvious is the bilobed pleotelson in C. gobii which is absent in C. capri. The defining pereonite 1 characters of C. collaris are absent in C. capri and differences between C. capri and C. italica include less developed eyes, acute and produced anterior margin of the cephalon and the more truncate body of C. italica. Similar characters separate it from C. steindachneri as well as the number of articles of the antennae and C. oxyrrhynchaena differs from C. capri in the shape of the 7th pereopod basis of the female. Lastly, C. oestroides is less globular or elliptical when compared to C. capri; is darker in the post-cephalic region due to more chromatophores; has shorter uropods; and a more stout body.
In the original description of this species,
Cymothoa
carinata
Bianconi, 1869: 210–211, pl. II, figs 2 (a–b).—
Cymothoa (Ceratothoa) carinata
.—
Ceratothoa
carinata
.—
Meinertia
carinata
.—
Codonophilus
carinatus
.—
Ceratothoa curvicauda Nunomura, 2006: 36–38, figs 12–13.
Ceratothoa
sp.—
Neotype [here designated]. South African Musuem, Cape Town (
Neotype female. Length 33 mm, width 15 mm.
Body rectangular, 1.8 times as long as greatest width, dorsal surface with medial longitudinal ridge present, widest at pereonites 3–5, most narrow at pereonite 1, lateral margins slightly convex. Cephalon 0.6 times longer than wide, visible from dorsal view, subtriangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins, one eye 0.1 times width of cephalon; 0.2 times length of cephalon. Antennula more stout and same length as antenna, with 7 articles; antennule peduncle articles 1 and 2 distinct and articulated. Antenna with 8 articles.
Pereonite 1 with median projection, anterior border straight, anterolateral angle with small distinct produced point, extend to middle of the eye. Posterior margins of pereonites smooth and straight. Coxae 2–3 narrow; with posteroventral angles rounded; 4–7 with rounded point; not extending past pereonite margin. Pereonites 6 and 7 narrower and becoming more progressively rounded posteriorly. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin with irregular small nodules. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonite 5 widest, posterior margin produced medially. Pleotelson 0.5 times as long as anterior width, dorsal surface with 2 sub-medial depressions, lateral margins weakly convex, posterior margin subtruncate and shallowly emarginate.
Pereopod 1 basis 1.5 times as long as greatest width; ischium 0.8 times as long as basis; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus 1.7 times as long as wide; dactylus moderately slender, 1.2 times as long as propodus, 2.9 times as long as basal width. Pereopod 7 basis as long as greatest width; ischium 1.2 times as long as basis, with a large proximal bulbous protrusion; merus proximal margin with large bulbous protrusion, merus 0.5 times as long as wide, 0.3 times as long as ischium; carpus 0.7 times as long as wide, 0.3 times as long as ischium, without bulbous protrusion; propodus 1.3 times as long as wide, 0.5 times as long as ischium; dactylus moderately slender, as long as propodus, 2.2 times as long as basal width.
Uropod same length as pleotelson, peduncle 0.8 times longer than rami, peduncle lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices narrowly rounded. Endopod apically rounded, 3 times as long as greatest width, lateral margin straight, mesial margin straight, terminating without setae. Exopod extending to end of endopod, 4 times as long as greatest width, apically rounded, lateral margin weakly convex, mesial margin straight, terminating without setae.
Ovigerous female: 28.5–38 mm TL (10–14 mm W); non-ovigerous female: 13–34 mm TL; male: 10–12 mm TL (
Western Indian Ocean and southwest Pacific Ocean: Mozambique (
On Lutjanus adetii (previously L. amabilis) (
Ceratothoa carinata can be identified by the characteristic medial ridge extending longitudinally along the dorsal pereon surface. Furthermore, it has a laterally depressed and wider than long pleotelson; pereonite 7 with an enlarged carinate ischium and large bulbous protrusion on the merus; uropods reaching the distal edge of the pleotelson; as well as a concave posterior margin on the pleotelson.
Species and names within Ceratothoa have been moved in and out of synonymy, an indication of both the difficulty of identifying and characterising species. Furthermore, many species are variable (
As the current specimen is undoubtedly C. carinata, it is hereby designated as the neotype for the species, fulfilling all of the requirements necessary in the International Code of Zoological Nomenclature (Anon 1999, ICZN, Article 75).
Cymothoa
oestroïdes.—
Ceratothoa
collaris
Schioedte & Meinert, 1883: 366–368, tab. XVI (Cym. XXIII) figs 8–9.—
Meinertia
collaris
forma
typica
.—
Meinertia
collaris
forma
africana
.—
Meinertia
collaris
forma
globuligera
.—
Meinertia
collaris
.—
Ceratothoa
collaris
forma
africana
.—
Ceratothoa
collaris
forma
typica
.—
Holotype. National Museum of Natural History, Paris (
Holotype female. Length 40 mm, width 18 mm.
Body oval, 1.8 times as long as greatest width, dorsal surfaces slightly bumpy, widest at pereonite 4 and pereonite 5, most narrow at pereonite 1, lateral margins posteriorly ovate. Cephalon 0.6 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins. Antennula more stout than antenna, shorter than antenna, with 7 articles. Antenna with 8 articles.
Pereonite 1 with slight indentations, anterior border straight, anterolateral angle with distinct anterior projection, extend to middle of the eye. Posterior margins of pereonites smooth and slightly curved laterally. Coxae 2–3 narrow; with posteroventral angles rounded; 4–7 acute, posteriorly pointed; not extending past pereonite margin. Pereonites 1–4 increasing in length and width; 5–7 decreasing in length and width; becoming more progressively rounded posteriorly. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin smooth, mostly concave. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin produced medially. Pleotelson 0.4 times as long as anterior width, dorsal surface with medial furrow, lateral margins weakly convex, posterior margin damaged and shallowly emarginate.
Pereopod 1 basis 1.7 times as long as greatest width; ischium 0.6 times as long as basis; merus proximal margin with bulbous protrusion; carpus with rounded proximal margin; propodus 1.6 times as long as wide; dactylus slender, 0.9 times as long as propodus, 2.1 times as long as basal width. Pereopod 7 basis 1.4 times as long as greatest width; ischium 0.8 times as long as basis, without protrusions; merus proximal margin with large bulbous protrusion, merus 0.4 times as long as wide, 0.3 times as long as ischium; carpus 0.4 times as long as wide, 0.2 times as long as ischium, without bulbous protrusion; propodus 0.9 times as long as wide, 0.4 times as long as ischium; dactylus slender, 1.5 times as long as propodus, 2.3 times as long as basal width.
Uropod more than half the length of pleotelson, peduncle 0.9 times longer than rami, peduncle lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices narrowly rounded. Endopod apically rounded, 3.6 times as long as greatest width. Exopod extending to end of endopod, 4 times as long as greatest width, apically rounded.
Female: 18–40 mm TL (9–18 mm W); male: 9–22 mm TL (4–10 mm W); second pullus: 2.7–2.8 mm TL (0.7–0.8 mm W) (
Mediterranean and eastern Atlantic Ocean: Algeria (
Ceratothoa collaris is common in Tunisia (
Frequently in the mouth of sparids from the genera Dentex and Pagellus (especially Dentex gibbosus and Pagellus erythrinus): D. gibbosus (previously D. filosus) (see
Ceratothoa collaris can be distinguished by the prominent anterolateral projections which do not extend past the eyes and form a collar-like structure from where it gets its name. It also has a wide pleotelson (same width or wider than pleon), uropods that do not extend past the pleotelson and a large bulbous protrusion on the pereopod 7 merus.
Ceratothoa collaris was described from Algeria, originally misidentified as C. oestroides by
Meinertia
gilberti
Richardson, 1904: 53, figs 32–33;
Codonophilus
gilberti
.—
Meinertia
sp.—
Ceratothoa
gilberti
.—
Lectotype [here designated]. United States National Museum, USA (
Lectotype female. Length 22 mm, width 9.5 mm.
Body oval, 1.8 times as long as greatest width, dorsal surfaces slightly bumpy, widest at pereonite 4 and pereonite 5, most narrow at pereonite 1, lateral margins posteriorly ovate. Cephalon 0.6 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins. Antennula more stout than antenna, shorter than antenna, with 7 articles. Antenna with 8 articles.
Pereonite 1 with slight indentations, anterior border straight, anterolateral angle with distinct anterior projection, extend to middle of the eye. Posterior margins of pereonites smooth and slightly curved laterally. Coxae 2–3 narrow; with posteroventral angles rounded; 4–7 acute, posteriorly pointed; not extending past pereonite margin. Pereonites 1–4 increasing in length and width; 5–7 decreasing in length and width; becoming more progressively rounded posteriorly. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin smooth, mostly concave. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin produced medially. Pleotelson 0.4 times as long as anterior width, dorsal surface with medial furrow, lateral margins weakly convex, posterior margin damaged and shallowly emarginate.
Pereopod 1 basis 1.7 times as long as greatest width; ischium 0.6 times as long as basis; merus proximal margin with bulbous protrusion; carpus with rounded proximal margin; propodus 1.6 times as long as wide; dactylus moderately slender, 0.9 times as long as propodus, 2.1 times as long as basal width. Pereopod 7 basis 1.4 times as long as greatest width; ischium 0.8 times as long as basis, without protrusions; merus proximal margin with large bulbous protrusion, merus 0.4 times as long as wide, 0.3 times as long as ischium; carpus 0.4 times as long as wide, 0.2 times as long as ischium, without bulbous protrusion; propodus 0.9 times as long as wide, 0.4 times as long as ischium; dactylus slender, 1.5 times as long as propodus, 2.3 times as long as basal width.
Uropod more than half the length of pleotelson, peduncle 0.9 times longer than rami, peduncle lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices narrowly rounded. Endopod apically rounded, 3.6 times as long as greatest width. Exopod extending to end of endopod, 4 times as long as greatest width, apically rounded.
Female: 16–29 mm TL (8–14 mm W) (
Known from the south-western coast of northern America in the Gulf of California region: from southern California, USA (
On tongue of the mullet Mugil cephalus (see
Ceratothoa gilberti has an elongate body; pleon as wide as pereon; short uropods; a elongate, triangular cephalon; short anterolateral projections on pereonite 1; and a large pleotelson with a rounded posterior margin. Furthermore,
Ceratothoa gilberti has been infrequently collected and seems to be confined to the region around the Gulf of California. It has only been found on mullet species and has often been compared to C. gaudichaudii (which has recently been placed into species inquirenda by Martin et al. [2015]).
Ceratothoa Gobii Schioedte & Meinert, 1883: 356–358, tab. XV (Cym. XXII) figs 12–13.
Ceratothoa
gobii
.—
Meinertia
gobii
.—
Holotype. Museum of Comparative Zoology, USA (
Holotype female. Length 12 mm, width 5 mm.
Body elongate, 1.9 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5, most narrow at pereonite 1, lateral margins slightly convex. Cephalon 0.7 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins, one eye 0.3 times width of cephalon; 0.6 times length of cephalon.
Pereonite 1 smooth, anterior border straight, anterolateral angle with small distinct produced point and produced past frontal margin of cephalon, extend to middle of the eye. Posterior margins of pereonites smooth and straight. With posteroventral angles rounded; coxae 4–7 rounded; not extending past pereonite margin. Pereonites 1–5 increasing in length and width; 6–7 decreasing in length and width; becoming more progressively rounded posteriorly. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin smooth, mostly concave. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin produced medially. Pleotelson 0.4 times as long as anterior width, dorsal surface smooth, lateral margins weakly convex, posterior margin subtruncate and shallowly emarginate.
Pereopod 1 basis 1.4 times as long as greatest width; ischium 0.7 times as long as basis; merus proximal margin with bulbous protrusion; carpus with rounded proximal margin; propodus 1.7 times as long as wide; dactylus slender, as long as propodus, 3 times as long as basal width. Pereopod 7 basis as long as greatest width; ischium 0.8 times as long as basis, without protrusions; merus proximal margin with large bulbous protrusion, merus 0.4 times as long as wide, 0.3 times as long as ischium; carpus 0.7 times as long as wide, 0.3 times as long as ischium, with slight bulbous protrusion; propodus 1.1 times as long as wide, 0.4 times as long as ischium; dactylus slender, 1.6 times as long as propodus, 2.7 times as long as basal width.
Uropod same length or slightly longer than the pleotelson, peduncle 0.6 times longer than rami, peduncle lateral margin without setae; rami extending beyond pleotelson, marginal setae absent, apices narrowly rounded. Exopod extending to end of endopod.
Ceratothoa gobii has a triangular cephalon with a sub-truncate rostrum; large eyes which together take up more than half of the cephalon; uropods which extend past the posterior margin of the pleotelson; short anterolateral projections on pereonite 1; and pleonites 1–5 gradually becoming wider.
This species is based on the description of a single specimen by
Meinertia guttata Richardson, 1910: 20–21, fig. 19.
Codonophilus
guttatus
.—
Meinertia venusta Avdeev, 1978: 30–32, pl. 1.
Ceratothoa
venusta
.—
Ceratothoa
guttata
.—
Lectotype [here designated]. United States National Museum, USA (
Lectotype female. Length 17 mm, width 7 mm.
Body oval and elongate, twice as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5, most narrow at pereonite 1, lateral margins ovate. Cephalon 0.6 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes irregular in outline. Antennula and antenna stout and same length. Antennula with 7 articles, antenna with 8 articles.
Pereonite 1 smooth, anterior border straight, anterolateral angle with small distinct anterior projection extending to base of eyes. Posterior margins of pereonites slightly produced medially. Coxae 2–3 wide, with posteroventral angles rounded; 4–7 large and produced on pereonite margins, not extending past pereonite margin. Pereonites 1–5 increasing in length and width; 6–7 decreasing in length and width; 2–5 subequal. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin smooth, mostly concave. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 forming acute point. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin produced medially. Pleotelson 0.6 times as long as anterior width, dorsal surface smooth, lateral margins weakly convex, posterior margin shallowly emarginate.
Pereopod 1 basis 1.5 times as long as greatest width; ischium 0.8 times as long as basis; merus proximal margin with large bulbous protrusion; carpus with straight proximal margin; propodus as long as wide; dactylus slender, 1.4 times as long as propodus, 2.4 times as long as basal width. Pereopod 7 basis 0.8 times as long as greatest width; ischium 1.3 times as long as basis, with a large proximal bulbous protrusion overlapping merus; merus proximal margin with large distal bulbous protrusion, merus 0.7 times as long as wide, 0.3 times as long as ischium; carpus 0.7 times as long as wide, 0.3 times as long as ischium, without bulbous protrusion; propodus 1.4 times as long as wide, 0.5 times as long as ischium; dactylus slender, 1.4 times as long as propodus, 2.6 times as long as basal width.
Uropod more than half the length of pleotelson, peduncle 0.8 times longer than rami.
. Holotype of Ceratothoa venusta. Russian Pacific Federal Fisheries Research Institute (AGK 75054) – on flying fish, Parexocoetus brachypterus, from the Red Sea (
Ovigerous females: 14.5–23.0 mm TL; non-ovigerous females: 15.5–16.5 mm TL; males: 5.4–7.4 mm TL (
Central and Western Indo-Pacific: Philippines (
In mouths of flying fish, Parexocoetus brachypterus (see
Ceratothoa guttata is distinguished by the elongate body widest at pereonite 5; uropods which do not extend past the posterior margin of the pleotelson; a narrow pleon; an expanded merus on pereopod 1; and an expanded ischium and merus on pereopod 7.
Ceratothoa guttata is considered to be highly host specific as it has, to date, only been reported from a single host, Parexocoetus brachypterus.
Ceratothoa
italica
Schioedte & Meinert, 1883: 347–350, tab. XV (Cym. XXII), figs 1–4.—
Meinertia
italica
.—
Identity uncertain: Ceratothoa italica.—
Lectotype [here designated]. Zoological Museum, University of Copenhagen (
Lectotype female. Length 36 mm, width 17 mm.
Body rectangular and elongate, 1.7 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5 and pereonite 6, most narrow at pereonite 1, lateral margins subparallel. Cephalon 0.5 times longer than wide, visible from dorsal view, triangular. Eyes irregular in outline, one eye 0.2 times width of cephalon; 0.2 times length of cephalon.
Pereonite 1 with unique bulbous orientation, anterior border anteriorly produced medially, anterolateral angle wide, with inwardly produced point, extend to anterior margin of eyes. Posterior margins of pereonites slightly produced medially. Coxae 4–7 rounded, not extending past pereonite margin. Pereonites 1–4 increasing in length and width; 5–7 decreasing in length and width; 6 and 7 narrower and becoming more progressively rounded posteriorly. Pleon with pleonite 1 same width as other pleonites (except pleonite 5), visible in dorsal view; pleonites posterior margin smooth, mostly concave. Posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin with 2 indented points. Pleotelson 0.5 times as long as anterior width, dorsal surface with medial furrow, lateral margins weakly convex, posterior margin subtruncate.
Pereopod 1 basis 1.5 times as long as greatest width; ischium 0.9 times as long as basis; merus proximal margin with large bulbous protrusion; carpus with straight proximal margin; propodus 1.1 times as long as wide; dactylus slender, 1.2 times as long as propodus, 2.3 times as long as basal width. Pereopod 7 basis 1.2 times as long as greatest width; ischium 0.8 times as long as basis, without protrusions; merus proximal margin with slight bulbous protrusion, merus 0.5 times as long as wide, 0.4 times as long as ischium; carpus 0.5 times as long as wide, 0.3 times as long as ischium, without bulbous protrusion; propodus 1.1 times as long as wide, 0.5 times as long as ischium; dactylus slender, 1.4 times as long as propodus, 2.5 times as long as basal width.
Uropod same length as pleotelson, peduncle 0.5 times longer than rami, peduncle lateral margin without setae; rami extending to pleotelson apex, marginal setae absent, apices narrowly rounded.
Ovigerous female: 15–30 mm TL; male: 8–15 mm TL; second pullus: 3 mm TL (
Mediterranean region and north-western Africa: Adriatic Sea (
In mouth of Spondyliosoma cantharus (previously Cantharus lineatus) (
Ceratothoa italica can be distinguished by the arched body; large bulbous protrusion on the merus of pereopod 1; a pointed rostrum; and uropods that do not extend past the pleotelson. This species also has a prominent projection in the middle of pereonite 1 (hump-like) and a pleon which is usually as wide as the pereon.
The female
Canolira œstroïdes Risso, 1826: 123.
Cymothoa
oestroides
.—
Cymothoa (Meinertia) oestroides
.—
Ceratothoa
oestroides
.—
Ceratothoa sargorum Gourret, 1891: 16, pl. 1, fig. 17; pl. 5, figs 1–4.
Meinertia
oestroides
.—Thielemann, 1910: 36.—
Cymothea
oestroides
[sic].—
Ceratothoa (Meinertia) oestroides
.—
Not Cymothoa oestroides.—
Excluded (identity uncertain): Meinertia oestroides.—
Ceratothoa
oestroides
.—
Lectotype [here designated]. National Museum of Natural History, Paris (
Lectotype female. Length 22 mm, width 8 mm.
Body oval and elongate, 1.9 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 4 and pereonite 5, most narrow at pereonite 1, lateral margins posteriorly ovate. Cephalon 0.6 times longer than wide, visible from dorsal view, triangular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margins, one eye 0.3 times width of cephalon; 0.4 times length of cephalon. Antennula more stout than antenna, comprised of 7 articles. Antenna comprised of 8 articles.
Pereonite 1 smooth, anterior border straight, anterolateral angle with small distinct produced point, extend to middle of the eye. Posterior margins of pereonites smooth and slightly curved laterally. Coxae 2–3 narrow, with posteroventral angles rounded; 4–7 rounded, not extending past pereonite margin. Pereonites 1–4 increasing in length and width; 5–7 decreasing in length and width; 6 and 7 narrower. Pleon with pleonite 1 most narrow and same width as other pleonites, visible in dorsal view; pleonites posterior margin smooth, mostly concave. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin with 2 indented points or produced medially. Pleotelson 0.5 times as long as anterior width, dorsal surface with lateral indent, lateral margins weakly convex, posterior margin rounded with medial indent.
Pereopod 1 basis 1.7 times as long as greatest width; ischium 0.6 times as long as basis; merus proximal margin with large bulbous protrusion; carpus with rounded proximal margin; propodus 1.5 times as long as wide; dactylus slender, 0.9 times as long as propodus, 2.3 times as long as basal width. Pereopod 7 basis 1.1 times as long as greatest width; ischium 0.9 times as long as basis, with slight bulbous protrusion; merus proximal margin with large bulbous protrusion, merus 0.6 times as long as wide, 0.3 times as long as ischium; carpus 0.7 times as long as wide, 0.3 times as long as ischium, without bulbous protrusion; propodus 1.4 times as long as wide, 0.6 times as long as ischium; dactylus slender, 0.9 times as long as propodus, 2.4 times as long as basal width.
Uropod same length or slightly longer than the pleotelson, peduncle 0.8 times longer than rami, peduncle lateral margin without setae; rami extending to pleotelson apex, marginal setae absent, apices narrowly rounded.
Ovigerous female: 12–30 mm; non-ovigerous female: 11–24.5 mm TL; male: 3.5–13 mm TL; second stage pullus: 3.3–4 mm TL; first stage pullus: 3.1 mm TL (
Throughout the Mediterranean and eastern Atlantic: especially France and Algeria (
Common in the mouth and branchial regions of the bogue, Boops boops (see
Ceratothoa oestroides can be distinguished by having an acute rostrum; short antennae; prominent eyes; uropods which extend to or past the posterior pleotelson margin; large protrusion on the merus of pereonite 1; and a large carina on pereopod 7 in female specimens, as well as the appendix masculina absent in male specimens.
Ceratothoa sargorum Gourret, 1891, found on Sargus rondeletii, was described from a single female with large eggs, almost a millimetre in diameter (
There have been reported cases of C. oestroides involved in hyperparasitism.
Ceratothoa oestroides has often been misidentified as C. oxyrrhynchaena. Both species use similar host fish and have an overlapping distribution range, but they are distinguished by the morphology of the seventh pair of pereopods in the female. It should be noted that male C. oestroides does not possesses an appendix masculina. We regard the records of Ceratothoa oestroides from the Caribbean (
Oniscus Ceti Spengler, 1775: 312 [nomen nudum].
Rhexana
verrucosa
Schioedte & Meinert, 1883: 291–296, tab. XI (Cym. XVIII) figs 5–10.—
Rhexanella
verrucosa
.—
Ceratothoa
verrucosa
.—
Identity uncertain: Rhexanella verrucosa.—
Lectotype. National Museum of Natural History (Naturalis), Leiden, Netherlands (
Lectotype female. Length 40 mm, width 21 mm.
Body oval, 1.9 times as long as greatest width, dorsal surfaces slightly bumpy, widest at pereonite 4, most narrow at pereonite 1, lateral margins slightly convex. Cephalon 0.7 times longer than wide, visible from dorsal view, subtriangular. Frontal margin rounded to form blunt rostrum. Eyes irregular in outline. Pereonite 1 with unique bulbous orientation, anterior border slightly indented, anterolateral angle with large wide projections, extend to anterior margin of eyes. Posterior margins of pereonites slightly damaged and bumpy. Coxae 2–3 wide; 4–7 large and produced on pereonite margins, not extending past pereonite margin. Pereonites subequal. Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin not smooth, mostly concave. Pleonite 2 not overlapped by pereonite 7; posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3–5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin produced medially. Pleotelson 0.5 times as long as anterior width, dorsal surface with lateral indent, lateral margins weakly convex, posterior margin evenly rounded. Antennula more stout than antenna, same length as antenna, consisting of 7 articles. Antenna consisting of 9 articles.
Pereopod 1 basis 1.4 times as long as greatest width; ischium 0.7 times as long as basis; merus proximal margin with large bulbous protrusion; carpus with rounded proximal margin; propodus 1.2 times as long as wide; dactylus slender, 0.9 times as long as propodus, 1.9 times as long as basal width. Pereopod 7 basis 0.8 times as long as greatest width; ischium as long as basis, with slight bulbous protrusion; merus proximal margin with large bulbous protrusion, merus 0.4 times as long as wide, 0.3 times as long as ischium; carpus 0.6 times as long as wide, 0.9 times as long as ischium, without bulbous protrusion; propodus 0.7 times as long as wide, 0.4 times as long as ischium; dactylus slender, 1.8 times as long as propodus, twice as long as basal width.
Uropod half the length of pleotelson, peduncle as long as rami, peduncle lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices narrowly rounded.
Ovigerous females: 27–50 mm TL (15.5–25.5 mm W); non-ovigerous females 20.5–40 mm TL; males 15–35 mm TL (11 mm W); larvae 3.5 mm TL (
Known from Japan and surrounding islands (
In the mouth of Pagrus major (previously Pagrosomus major) (“Tai” in Japanese) (
Ceratothoa verrucosa is distinguished by the large, oval body; wide anterolateral projections on pereonite 1; pleon as wide as pereon; and short uropods not extending to the posterior margin of the pleotelson.
This species was originally thought to infect a Greenland whale (
Codonophilus
argus
Haswell, 1881: 471, pl. XVI, fig. 1;
Deposition unknown.
Australia (
Under the bell of a Rhizostoma (see
This species was described from an immature specimen (4 mm in length) in only a few sentences and a single figure. It was found under the bell of a Rhizostoma in Port Jackson (Sydney, New South Wales) and noted as being similar to Aegathoa in many ways, but differed in the sudden narrowing of the body at the commencement of the pleon, and the uniramous character of the caudal appendages.
Due to the species being based on a single immature specimen (as well as a lack of a type specimen and an incomplete description), this species is hereby considered nomen dubium.
Meinertia poutassouiensis Brian, 1939: 20–24 [nomen nudum].
Meinertia (Ceratothoa) potassoniensis
.—
Ceratothoa
poutassouiensis
.—
Micromesistius poutassou (previously Gadus potassoa).
These two species names, published in the same year, refer to the same species.
Meinertia transversa Richardson, 1900: 221 [nomen nudum].
Meinertia
transversa
Richardson, 1901: 529–530, figs 12–13;
Ceratothoa
transversa
.—
Holotype. United States National Museum, USA (
Between the Mississippi Delta and Cedar Keys, Florida (
Unknown.
Ceratothoa transversa was originally noted as having a cephalon only slightly immersed in pereonite 1; long antennae extending past pereonite 1; uropods slightly longer than the pleotelson; and a sub-triangular pleotelson.
Examination of the holotype confirmed that it is an immature specimen. The antennae extend into the middle of pereonite 1, the pleon is almost as wide as the pereon, there are a few setae on the uropods and pleotelson, the pleopods overlap and the appendix masculina is absent. Without an adult female to characterise the species, and no known hosts to assist in directing the collection of a new specimen, the identity of this species is uncertain and therefore C. transversa is hereby placed into species inquirenda.
Ceratothoa triglae Gourret, 1891: 19–20, pl. 11, figs 14–19.
Ceratothoa triglae (Gourret, 1891) was described from a male specimen measuring 7 mm TL.
Meinertia parva Richardson, 1910: 21, fig. 20.
Codonophilus
parvus
.—
Ceratothoa
parva
.—
Holotype. United States National Museum, USA (
Ceratothoa parva was originally described as having distinct eyes; rounded anterolateral processes on pereonite 1 which extend half the length of the cephalon; and short uropods which do not reach the end of the pleotelson.
Examination of the holotype revealed many characters not usually present in Ceratothoa. Pleonite 1 is as wide as the other pleonites (usually narrower), pleonite 4 is slightly wider than pleonite 5, slender and short antennae, and, most significantly, the bases of the antennae do not touch (a defining characteristic of Ceratothoa). These characters, together with the shape of the head and pereopod morphology all agree well with the generic characters for Elthusa Schioedte & Meinert, 1884 (see
A number of recent papers revising Ceratothoa (
Currently accepted species of Ceratothoa, their respective authorities and the most recent reference for each.
No. | Accepted name | Authority | Reference |
---|---|---|---|
1 | Ceratothoa africanae | Hadfield, Bruce & Smit, 2014 |
|
2 | Ceratothoa angulata | (Richardson, 1910b) | Present study |
3 | Ceratothoa arimae | (Nunomura, 2001) |
|
4 | Ceratothoa banksii | (Leach, 1818) |
|
5 | Ceratothoa barracuda | Martin, Bruce & Nowak, 2015 |
|
6 | Ceratothoa capri | (Trilles, 1964c) | Present study |
7 | Ceratothoa carinata | (Bianconi, 1869) | Present study |
8 | Ceratothoa collaris | Schioedte & Meinert, 1883 | Present study |
9 | Ceratothoa famosa | Hadfield, Bruce & Smit, 2014 |
|
10 | Ceratothoa gilberti | (Richardson, 1904) | Present study |
11 | Ceratothoa globulus | Martin, Bruce & Nowak, 2015 |
|
12 | Ceratothoa gobii | Schioedte & Meinert, 1883 | Present study |
13 | Ceratothoa guttata | (Richardson, 1910b) | Present study |
14 | Ceratothoa imbricata | (Fabricius, 1775) | Hadfield et al. 2014 |
15 | Ceratothoa italica | Schioedte & Meinert, 1883 | Present study |
16 | Ceratothoa marisrubri | Trilles, Colorni & Golani, 1999 | Present study |
17 | Ceratothoa oestroides | (Risso, 1826) | Present study |
18 | Ceratothoa oxyrrhynchaena | Koelbel, 1878 | Present study |
19 | Ceratothoa parallela | (Otto, 1828) | Present study |
20 | Ceratothoa retusa | (Schioedte & Meinert, 1883) |
|
21 | Ceratothoa steindachneri | Koelbel, 1878 | Present study |
22 | Ceratothoa trigonocephala | (Leach, 1818) |
|
23 | Ceratothoa usacarangis | (Avdeev, 1979a) | Present study |
24 | Ceratothoa verrucosa | (Schioedte & Meinert, 1883) | Present study |
Species previously placed in combination with Ceratothoa, together with the current status and most recent reference. Full synonymies and nomenclatural details may be found in
No. | Former combination | Status | Reference |
---|---|---|---|
1 | Ceratothoa argus (Haswell, 1881) | nomen dubium (no type, immature specimen) | Present study |
2 | Ceratothoa atherinae (Gourret, 1891) | = Mothocya epimerica (junior synonym) | Monod 1923c |
3 | Ceratothoa brachyura (White, 1847) | nomen nudum (no type, no description) | Present study |
4 | Ceratothoa contracta (Miers, 1880) | species inquirenda (type not located) |
|
5 | Ceratothoa crassa Dana, 1853 | Glossobius crassa |
|
6 | Ceratothoa curvicauda Nunomura, 2006 | = Ceratothoa carinata (junior synonym) |
|
7 | Ceratothoa deplanata Bovallius, 1885 | = Ceratothoa parallela (junior synonym) |
|
8 | Ceratothoa directa (Otto, 1821) | = Ceratothoa parallela (junior synonym) |
|
9 | Ceratothoa exocoeti Cunningham, 1871 | = Glossobius impressus (junior synonym) |
|
10 | Ceratothoa gaudichaudii (Milne Edwards, 1840) | species inquirenda (no female type) | Martin et al. 2015 |
11 | Ceratothoa hemirhamphi (Pillai, 1954) | = Ceratothoa retusa (junior synonym) |
|
12 | Ceratothoa huttoni Filhol, 1885 | = Ceratothoa imbricata (junior synonym) |
|
13 | Ceratothoa impressa Say, 1818 | = Glossobius impressus (junior synonym) |
|
14 | Ceratothoa laticauda Milne Edwards, 1840 | = Glossobius auritus (junior synonym) |
|
15 | Ceratothoa linearis Dana, 1853 | Glossobius linearis |
|
16 | Ceratothoa lineata Miers, 1876 | Mothocya lineata |
|
17 | Ceratothoa novae–zelandiae Filhol, 1885 | = Ceratothoa trigonocephala (junior synonym) |
|
18 | Ceratothoa parva (Richardson, 1910b) | incertae sedis (not Ceratothoa, single specimen) | Present study |
19 | Ceratothoa potassoniensis (Penso, 1939) | nomen dubium (no type or description) | Present study |
20 | Ceratothoa poutassouiensis (Brian, 1939) | nomen nudum (no type or description) |
|
21 | Ceratothoa rapax Heller, 1865 | = Ceratothoa gaudichaudii (junior synonym) |
|
22 | Ceratothoa salparum Gourret, 1891 | = Emetha audouini (junior synonym) |
|
23 | Ceratothoa sargorum Gourret, 1891 | = Ceratothoa oestroïdes (junior synonym) |
|
24 | Ceratothoa transversa (Richardson, 1901) | species inquirenda (immature specimen) | Present study |
25 | Ceratothoa triglae Gourret, 1891 | species inquirenda (no type, male specimen) | Present study |
26 | Ceratothoa trillesi (Avdeev, 1979a) | = Ceratothoa imbricata (junior synonym) |
|
27 | Ceratothoa venusta Avdeev, 1978 | = Ceratothoa guttata (junior synonym) |
|
A total of 50 Ceratothoa species names were found in the literature. Of these, 30 are regarded as valid (
The financial assistance of the National Research Foundation (NRF) towards this research is hereby acknowledged (NRF project IFR2011040100022, NJ Smit, PI and SFP12091012541, KA Hadfield, PI). Opinions expressed and conclusions arrived at, are those of the authors and are not necessarily to be attributed to the NRF. Further thanks to the Claude Leon Foundation for their financial support of KA Hadfield for part of this project. Our thanks thanks go to Liz Hoenson from the Iziko South African Museum, Cape Town; Adam Baldinger from Museum of Comparative Zoology; Laure Corbari from Muséum National d’Histoire Naturelle; Karen van Dorp from Naturalis Biodiversity Center; Charles Oliver Coleman from Museum für Naturkunde; Tom Schiøtte from Zoological Museum, University of Copenhagen; as well as Karen Reed and Karen Osborn from the Smithsonian National Museum of Natural History for access to the type material. Further thanks to Tammy Horton for her helpful assistance and comments in the preparation of this manuscript.