Fiddler Crab Systematics
Most of this information comes from:
Rosenberg, M. S. 2001. The systematics and taxonomy of fiddler crabs: A phylogeny of the genus Uca. Journal of Crustacean Biology 21(3):839-869.
Type species: Cancer vocans major Herbst, 1782
The earliest description of the type species of Uca is from a drawing in Seba (1758), which he called Cancer uka una, Brasiliensibus (shown below).
A number of authors subsequently used this same picture as a basis for naming the species (Manning and Holthuis, 1981). Cancer vocans major Herbst, 1782; Ocypode heterochelos Lamarck, 1801; Cancer uka Shaw and Nodder, 1802; and Uca una Leach, 1814, are all objective synonyms, because they are all based on the picture and description from Seba. Because of this, the official type specimen of the genus Uca is Cancer vocans major. The earliest description of this species based on actual specimens and not on Seba's drawing was Gelasimus platydactylus Milne-Edwards, 1837.
For about 60 years, the genus was known as Gelasimus, until Rathbun (1897) showed that the abandonment of the older name Uca did not conform to zoological naming conventions. The type species of Uca was known as both Uca heterochelos and U. platydactylus, until Rathbun (1918) suggested the adoption of U. heterochelos as the valid name. Almost 50 years later, Holthuis (1962) pointed out that U. heterochelos was an objective junior synonym of U. major, and the type species has been referred to as U. major ever since.
However, Bott (1973) discovered that there has been a universal misinterpretation of the type species; the species pictured by Seba is not the American species commonly referred to as U. major, but rather the West African/Portuguese species called U. tangeri (Eydoux, 1835). Correcting this error would have caused a somewhat painful change of names (Holthuis, 1979; Manning and Holthuis, 1981). The type species would still be called U. major, but would refer to the West African/European species rather than the American one; the American species, which has been called U. major since 1962, would be called U. platydactylus, a name not used since 1918.
To deal with this dilemma, the Society of Zoological Nomenclature officially designated the holotype of Gelasimus platydactylus as a neotype of Cancer vocans major (Holthuis, 1979; Opinion, 1983). The result of this decision is that we retain the names U. major for the American species and U. tangeri for the West African/European species. It also means that although U. tangeri is technically the species upon which the genus is named, U. major (Cancer vocans major) is still the official type species of the genus Uca.
There have been two major proposals for splitting up the genus, one by Bott (1973) and the other by Crane (1975). Neither is based on a numerical phylogeny. Crane's descriptions are very complete. Bott's descriptions are poor, but have priority. Most scientists have actively ignored both subdivisions. When there has been a reference in the literature, they have almost always been to Crane and not to Bott.
Based on an evaluation of the phylogeny of Uca and priority of publications, Rosenberg (2001) proposed the following subgenera:
Specific information on each subgenus is below. See Rosenberg (2001) for more details.
Type species: U. major
Species: U. heteropleura, U. insignis, U. intermedia, U. major, U.
maracoani, U. monolifera, U. ornata, U. princeps, U. stylifera, U. tangeri
This subgenus is a combination of Crane's Uca and Afruca.
Type species: U. mordax
Species: U. brevifrons, U. burgersi, U. ecuadoriensis, U. galapagensis, U.
herradurensis, U. longisignalis, U. marguerita, U. minax, U. mordax, U. panacea,
U. pugilator, U. pugnax, U. pygmaea, U. rapax, U. subcylindrica, U. thayeri, U.
umbratila, U. victoriana, U. virens, U. vocator, U. zacae
This subgenus is largely equivalent to a combination of Crane's Minuca and Boboruca. I have included U. pugilator and U. panacea, which are normally put in the Leptuca. U. thayeri and U. umbratila are sometimes put in their own subgenus; if so, it's name would be Planuca.
Type species: U. vocans
Species: U. borealis, U. dampieri, U. formosensis, U. hesperiae, U.
neocultrimana, U. tetragonon, U. vocans, U. vomeris
This subgenus is equivalent to Crane's Thalassuca. The exact status of U. formosensis is somewhat questionable. It may belong to the Tubuca or be in a new subgenus entirely. See Shih et al. (1999) and Rosenberg (2001) for more information.
Type species: U. chlorophthalmus
Species: U. chlorophthalmus, U. crassipes, U. inversa, U. sindensis
This subgenus is equivalent to Crane's Amphiuca.
Type species: U. stenodactylus
Species: U. annulipes, U. argillicola, U. batuenta, U. beebei, U. bengali,
U. coloradensis, U. crenulata, U. cumulanta, U. deichmanni, U. dorotheae, U.
festae, U. helleri, U. inaequalis, U. lactea, U. latimanus, U. leptochela, U.
leptodactyla, U. limicola, U. mjoebergi, U. musica, U. oerstedi, U. panamensis,
U. perplexa, U. saltitanta, U. speciosa, U. spinicarpa, U. stenodactylus, U.
tallanica, U. tenuipedis, U. terpsichores, U. tomentosa, U. triangularis
This subgenus is largely equivalent to Crane's Celuca. This subgenus is certainly paraphyletic and quite possibly polyphyletic. If the Indo-West Pacific species (U. annulipes, U. bengali, U. lactea, U. mjoebergi, U. perplexa, U. triangularis) are placed in their own subgenus, it would be called Austruca.
Type species: U. urvillei
Species: U. acuta, U. arcuata, U. capricornis, U. coarctata, U. demani, U.
dussumieri, U. flammula, U. forcipata, U. paradussumieri, U. rhizophorae, U.
rosea, U. typhoni, U. urvillei
This subgenus is equivalent to Crane's Deltuca.
Type species: U. bellator
Species: U. australiae, U. bellator, U. elegans, U. hirsutimanus, U.
longidigitum, U. polita, U. seismella, U. signata
List of species, subspecies, and synonyms
For an overview of all Uca species, the best reference is Crane (1975); any earlier major work would be overridden by Crane's descriptions. For the most part, the taxa recognized by Crane are still accepted today. A number of new species have been described since the publication of her monograph, one of her new species has been discovered to be invalid, and two of her new species were previously described by Bott (1973b); as with the subgenera, his names have priority and take precedence. These changes are summarized here:
| New Species | Reference |
|---|---|
| Note: The newly described species Uca pavo George and Jones, 1982, is a junior subsynonym of Uca capricornis (see von Hagen and Jones, 1989) | |
| Uca panacea | Novak and Salmon (1974) |
| Uca marguerita | Thurman (1981) |
| Uca elegans | George and Jones (1982) |
| Uca hirsutimanus | George and Jones (1982) |
| Uca intermedia | von Prahl and Toro (1985) |
| Uca victoriana | von Hagen (1987) |
| Junior Subsynonym | Correct Name | Reference(s) |
|---|---|---|
| Uca minima | Uca signata | George and Jones (1982) |
| Uca spinata | Uca paradussumieri | Dai and Yang (1991); Jones and Morton (1995) |
| Uca pacificensis | Uca neocultrimana | Rosenberg (2001) |
| Incorrect Spelling | Correct Spelling | Reference |
|---|---|---|
| Uca longidigita | Uca longidigitum | von Hagen and Jones (1989) |
| Uca mjobergi | Uca mjoebergi | von Hagen and Jones (1989) |
Crane (1975) tended to lump related taxa into subspecies rather than treat them as distinct species. A number of studies since that time have raised virtually all of her subspecies to specific status (e.g., Barnwell, 1980; Barnwell and Thurman, 1984; Collins et al., 1984; Green, 1980; Salmon et al., 1979; Salmon and Kettler, 1987; Thurman, 1979, 1982; von Hagen and Jones, 1989). It has become common practice with many authors to ignore all of the subspecific designations and treat each as a separate species (e.g., George and Jones, 1982; Jones and Morton, 1995; von Hagen and Jones, 1989). I follow this practice throughout this website.