Rajidae

Raja clavata, photographed by Jim Anderson.

Belongs within: Rajiformes.
Contains: Dipturus.

The Rajidae are the skates, a family of more than 200 species of generally diamond-shaped rays. Skates are benthic feeders on small invertebrates such as crustaceans and mollusks. Their eggs are laid in oblong cases with a curved horn at each corner, called 'mermaid's purses'. Hulley (1972) recognised two lineages within the Rajidae based on the structure of the claspers: in Dipturus, Leucoraja and related genera, a ventral structure composed of erectile tissue called the rhipidion is present. In Bathyraja and Raja, the rhipidion is absent and instead there is a dorsal cartilage-supported structure called the pseudorhipidion.

Characters (from McEachran 2002): Disk relatively thin, subcircular to trapezoid-shaped; tail slender to very slender, clearly marked off from disk. Rostrum extending to tip of snout; pectoral fins extending in front of nostrils to near tip of snout. Pelvic fins moderately laterally expanded, generally divided into anterior and posterior lobes, partially overlapped by posterior extension of pectoral fins. Tail generally one-half or more total length, usually slightly more slender distally, with two small dorsal fins and poorly developed caudal fin near tip; caudal fin usually consisting of low dorsal lobe and very short, low ventral lobe or ridge; lateral electric organs present on tail. Small dermal denticles and larger thorns usually present on various aspects of upper, and occasionally lower, disk. Females generally larger; males generally with more acute snout, undulated disk, more arched jaws, teeth with sharper cusps, alar and malar thorns on outer corners of upper disk; tips of alar thorns often embedded in integument, exposed with tips of pectoral fins are bent ventrally.

Rajidae
    |--+--Dipturus H72
    |  `--+--Amblyraja Stehmann 1970 H72, M02, H72 [incl. Deltaraia Leigh-Sharpe 1924 (nom. inv.)] H72
    |     |    |--*A. radiata (Donovan 1808) H72, M02 [=Raja (Amblyraja) radiata H72]
    |     |    |--A. duellojuradoi [=Raja (Amblyraja duellojuradoi] H72
    |     |    |--A. badia [=Raja (Amblyraja) badia] H72
    |     |    |--A. frerischi [=Raja (Amblyraja) frerischi] H72
    |     |    |--A. georgiana [=Raja (Amblyraja) georgiana] H72
    |     |    |--A. hypoborea [=Raja (Amblyraja) hypoborea] H72
    |     |    |--A. jenseni [=Raja (Amblyraja) jenseni] H72
    |     |    `--A. robertsi (Hulley 1970) [=Raja (Amblyraja) robertsi] H72
    |     `--+--Rajella Stehmann 1970 H72, M02, H72
    |        |    |--*R. fyllae (Lütken 1888) [=Raja (*Rajella) fyllae] H72
    |        |    |--R. bigelowi M02
    |        |    |--R. caudaspinosa (Von Bonde & Swart 1923) [=Raja (Rajella) caudaspinosa] H72
    |        |    |--R. confundens (Hulley 1970) [=Raja (Rajella) confundens] H72
    |        |    |--R. dissimilis (Hulley 1970) [=Raja (Rajella) dissimilis] H72
    |        |    |--R. lentiginosa [=Raja (Rajella) lentiginosa] H72
    |        |    |--R. leopardus (Von Bonde & Swart 1923) [=Raja (Rajella) leopardus] H72
    |        |    `--R. ravidula (Hulley 1970) [=Raja (Rajella) ravidula] H72
    |        `--Leucoraja Malm 1877 H72, M02, H72
    |             |--*L. fullonica (Linnaeus 1758) [=Raja (Leucoraja) fullonica] H72
    |             |--L. circularis [=Raja (Leucoraja) circularis] H72
    |             |--L. erinacea (Mitchill 1825) M02 [=Raja (Rajella) erinacea M02, H72]
    |             |--L. garmani M02 [=Raja (Rajella) garmani M02, H72]
    |             |    |--L. g. garmani M02
    |             |    `--L. g. virginica (McEachran 1977) M02
    |             |--L. lentiginosa M02
    |             |--L. leucosticta [=Raja (Leucoraja) leucosticta] H72
    |             |--L. naevus [=Raja (Leucoraja) naevus] H72
    |             |--L. ocellata (Mitchill 1815) M02 [=Raja (Rajella) ocellata M02, H72]
    |             `--L. wallacei (Hulley 1970) [=Raja (Leucoraja) wallacei] H72
    `--+--Bathyraja Ishiyama 1968 H72
       |    |--*B. isotrachys (Günther 1877) [=Raja isotrachys] H72
       |    |--B. abasiriensis H72
       |    |--B. aleutica H72
       |    |--B. diplotaenia H72
       |    |--B. matsubarai H72
       |    |--B. pallida H72
       |    |--B. richardsoni (Garrick 1961) M02
       |    |--B. smirnovi H72
       |    |    |--B. s. smirnovi H72
       |    |    `--B. s. ankasube H72
       |    |--B. smithii (Müller & Henle 1841) [incl. Raja eatoni] H72
       |    |--B. spinicauda M02
       |    |--B. tobitukai H72
       |    `--B. trachouros H72
       `--Raja Linnaeus 1758 H72
            |  i. s.: R. blanda H72
            |         R. brachyura H72
            |         R. eglanteria Bosc 1800 M02
            |         R. lemprieri Richardson 1846 G61
            |         R. lintea D56
            |         R. montagui LOL03
            |         R. murrayi H72
            |         R. ogilbyi Whitley 1939 G61
            |         R. polyommata G75
            |         R. porosa BJ06
            |         R. richardsoni Garrick 1961 G61
            |         R. schmidti BN03
            |         R. texana HC79
            |--R. (Raja) H72
            |    |--*R. (R.) miraletus Linnaeus 1758 H72
            |    |--R. (R.) clavata Linnaeus 1758 H72
            |    |--R. (R.) herwigi H72
            |    |--R. (R.) maderensis H72
            |    |--R. (R.) picta H72
            |    `--R. (R.) straeleni Poll 1951 H72
            `--R. (Rostroraja Hulley 1972) [incl. Iotaraia Leigh-Sharpe 1924 (nom. inv.)] H72
                 `--R. (*R.) alba Lacépède 1803 [incl. R. marginata] H72

Rajidae incertae sedis:
  Malacoraja Stehmann 1970 M02, H72
    |--M. senta (Garman 1885) [=Raja senta] M02
    `--M. spinacidermis (Barnard 1923) M02, G61 (see below for synonymy)
  Psammobatis H72
    |--P. extenta H72
    |--P. lima H72
    |--P. microps H72
    `--P. scobina H72
  Rhinoraja H72
    |--R. kujiensis H72
    |--R. longicauda H72
    `--R. odai H72
  Breviraja Bigelow & Schroeder 1948 H72
    `--B. colesi H72

Malacoraja spinacidermis (Barnard 1923) M02, G61 [=Raja (Malacoraja) spinacidermis H72; incl. R. mollis Bigelow & Schroeder 1950 H72, G61, R. (*Malacoraja) mollis H72]

*Type species of generic name indicated

REFERENCES

[BJ06] Bourlat, S. J., T. Juliusdottir, C. J. Lowe, R. Freeman, J. Aronowicz, M. Kirschner, E. S. Lander, M. Thorndyke, H. Nakano, A. B. Kohn, A. Heyland, L. L. Moroz, R. R. Copley & M. J. Telford. 2006. Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida. Nature 444 (7115): 85–89.

[BN03] Bourlat, S. J., C. Nielsen, A. E. Lockyer, D. T. J. Littlewood & M. J. Telford. 2003. Xenoturbella is a deuterostome that eats molluscs. Nature 424: 925–928.

[D56] Dawes, B. 1956. The Trematoda with special reference to British and other European forms. University Press: Cambridge.

[G61] Garrick, J. A. F. 1961. Studies on New Zealand Elasmobranchii. Part XIII. A new species of Raja from 1,300 fathoms. Transactions of the Royal Society of New Zealand 88 (4): 743–748.

[G75] Grant, E. M. 1975. Guide to Fishes. The Co-ordinator-General’s Department: Brisbane (Australia).

[HC79] Huff, J. A., & S. P. Cobb. 1979. Penaeoid and sergestoid shrimps (Crustacea: Decapoda). Memoirs of the Hourglass Cruises 5 (4): 1–101.

[H72] Hulley, P. A. 1972. The origin, interrelationship and distribution of southern African Rajidae (Chondrichthyes, Batoidei). Annals of the South African Museum 60 (1): 1–103.

[LOL03] Lockyer, A. E., P. D. Olson & D. T. J. Littlewood. 2003. Utility of complete large and small subunit rRNA genes in resolving the phylogeny of the Neodermata (Platyhelminthes): implications and a review of the cercomer theory. Biological Journal of the Linnean Society 78: 155–171.

[M02] McEachran, J. D. 2002. Skates. Family Rajidae. In: Collette, B. B. & G. Klein-MacPhee (eds) Bigelow and Schroeder’s Fishes of the Gulf of Maine, 3^rd ed. pp. 60–75. Smithsonian Institute Press: Washington.