Unidentified Polycopidae, copyright Agnieszka Mackiewicz.

Belongs within: Halocypridida.

The Polycopidae are a group of small ostracods with the first and second antennae modified for swimming, and the thoracic limbs reduced in number (Benson et al. 1961). Though fossils have been assigned to this family going back to the earliest Carboniferous, the record is discontinuous with no known representatives for most of the intervening period (Whatley et al. 1993).

Characters (from Benson et al. 1961): Mostly rather small, less than 0.8 mm (except some doubtful Palaeozoic taxa). Carapace subcircular in lateral outline, without gape of any kind; muscle scar pattern composed of three closely juxtaposed scars. Eyes absent. First antennae (antennules) natatory, not geniculate, terminated by small bundle of long setae. Second antennae biramous, both rami fully evolute, mobile and natatory. Mandibles bearing short, very small, pediform palp that serves as a branchial appendage. Two pairs of thoracic limbs present; anterior pair large, bifid, natatory; posterior pair membranous and branchial. Postabdomen divided into two furcal rami pointed posteriorly.

<==Polycopidae [Polycopoidea]
    |  i. s.: ‘Discoidella’ spaerula (Gründel 1961)WSB93
    |--Parapolycope Klie 1936DH86
    |    |--*P. germanica Klie 1936BB61
    |    |--P. kunashiri Chavtur 1977DH86
    |    `--P. rossica Chavtur 1977DH86
    |--Polycopsis Müller 1894DH86
    |    |--*P. compressa (Brady & Robertson 1869) [=Polycope compressa]BB61
    |    |--P. pacifica Chavtur 1977DH86
    |    `--P. serrata Müller 1894DH86
    `--Polycope Sars 1866ZL87 [incl. Cypridinopsis Armstrong 1871BB61]
         |--*P. orbicularis Sars 1866BB61
         |--P. aidae Hartmann 1959DH86
         |--P. angulata Chavtur 1977DH86
         |--P. antarctica Müller 1908DH86
         |--P. arenicola Hartmann 1954DH86
         |--P. areolata Sars 1923DH86
         |--P. bahamensis Kornicker 1959DH86
         |--P. brevis Müller 1908DH86
         |--P. cancellea Hartmann 1954DH86
         |--P. corallicola Hartmann 1974DH86
         |--P. coralligena Bonaduce, Ciliberto et al. 1982DH86
         |--P. crassidenta Chavtur 1977DH86
         |--P. demulderi Sissingh 1972DH86
         |--P. dentata Brady 1868DH86
         |--P. denticulata Bonaduce, Masoli et al. 1980DH86
         |--P. difficilis Klie 1936DH86
         |--P. dimorpha Hartmann 1954DH86
         |--P. dispar Müller 1894DH86
         |--P. duplidentata Hartmann 1959DH86
         |    |--P. d. duplidentataH59
         |    `--P. d. majanguerae Hartmann 1959H59
         |--P. elongata Hartmann 1954DH86
         |--P. essybaiensis Hartmann 1974DH86
         |--P. fragilis Müller 1894DH86
         |--P. frequens Müller 1894DH86
         |--P. gongxianensis Zhang in Zhang & Liang 1987ZL87
         |--P. helgolandica Klie 1936DH86
         |--P. krylatcki Chavtur 1977DH86
         |--P. kurilensis Chavtur 1977DH86
         |--P. levis Hartmann 1954DH86
         |--P. limbata Hartmann 1954DH86
         |--P. longipes Hartmann 1954DH86
         |--P. loscobanosi Hartmann 1959DH86
         |--P. maculata Müller 1894DH86
         |--P. marci Hartmann 1954DH86
         |--P. microdispar Hartmann 1954DH86
         |--P. minuta Hartmann 1974DH86
         |--P. minutissima Hartmann 1974DH86
         |--P. noodti Hartmann 1959DH86
         |--P. obtusa Hartmann 1954DH86
         |--P. onkophora Hartmann 1954DH86
         |--P. ornata Bonaduce, Masoli et al. 1980DH86
         |--P. paramushiri Chavtur 1977DH86
         |--P. parareticulata Bonaduce, Ciampo & Masoli 1975DH86
         |--P. pseudoorbicularis Chavtur 1977DH86
         |--P. pseudoputjatini Chavtur 1977DH86
         |--P. putjatini Chavtur 1977DH86
         |--P. quasisymmetrica Hartmann 1974DH86
         |--P. ramosa Hartmann 1954DH86
         |--P. ramunchensis Hartmann 1962DH86
         |--P. reticulata Müller 1894DH86
         |--P. rostrata Müller 1894DH86
         |--P. schulzi Klie 1950DH86
         |--P. seridentata Hartmann 1959DH86
         |--P. siewingi Hartmann 1958DH86
         |--P. striata Müller 1894DH86
         |--P. sublaevisBB61
         |--P. teneriffae Hartmann 1959DH86
         `--P. tuberosa Müller 1894DH86

*Type species of generic name indicated


[BB61] Benson, R. H., J. M. Berdan, W. A. van den Bold, T. Hanai, I. Hessland, H. V. Howe, R. V. Kesling, S. A. Levinson, R. A. Reyment, R. C. Moore, H. W. Scott, R. H. Shaver, I. G. Sohn, L. E. Stover, F. M. Swain & P. C. Sylvester-Bradley. 1961. Systematic descriptions. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt Q. Arthropoda 3: Crustacea: Ostracoda pp. Q99–Q421. Geological Society of America and University of Kansas Press.

[DH86] Danielopol, D. L., & G. Hartmann. 1986. Ostracoda. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 265–294. E. J. Brill/Dr W. Backhuys: Leiden.

[H59] Hartmann, G. 1959. Zur Kenntnis der lotischen Lebensbereiche der pazifischen Küste von El Salvador unter besonderer Berücksichtigung seiner Ostracodenfauna. Kieler Meeresforschungen 76 (2): 187–241.

[L05] Liebau, A. 2005. A revised classification of the higher taxa of the Ostracoda (Crustacea). Hydrobiologia 538: 115–137.

[WSB93] Whatley, R. C., D. J. Siveter & I. D. Boomer. 1993. Arthropoda (Crustacea: Ostracoda). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 343–356. Chapman & Hall: London.

[ZL87] Zhang X.-J. & Liang X.-Y. 1987. Ostracoda from the Taiyuan Formation of Xingyang and Gong Xian districts, Henan. Acta Micropalaeontologica Sinica 4 (3): 293–312.

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