Illinois Natural History Survey - University of Illinois

Paxyodon syrmataphorus (Meuschen, 1781)

ANSP 125546. Orinoco P. syrmataphorus

ANSP 125546. Orinoco

distribution map for P. symataphorus in Venezeula


Original Description: Mya syrmataphora Meuschen in Gronovius, L.T. 1781. p. 260. species no. 1093. pl XVIII, figs. 1 and 2 in Zoophylacium Gronovianum, exhibens, Animalia, Quadrupeda, Amphibia, Pisces, Insecta, Vermes, Mollusca, Testacea, et Zoophyta.

Type Locality: "Habitat in fluminibus Guineae."

Holotype: Location unknown.

Synonymy:

  • Triquetra subviridis Klein 1753
  • Klein 1753:135, pl. 9, fig. 36. Type locality: Guiana and Brazil?
  • Mya syrmataphora Meuschen, 1781

  • Meuschen in Gronovius, 1781:260, pl. 18, figs. 1, 2; Wood, 1825:12, pl. 2, fig. 36b.
  • Paxyodon ponderosus Schumacher, 1817

  • Schumacher 1817:46, pl. 11, fig. 3. Type locality: ???
  • Hyria syrmatophora (Meuschen, 1781)

  • Sowerby 1823, fig. d; 1839, fig. 143; Reeve, 1841:120, pl. 90, fig. 1; Wood, 1856:17, pl. 2, fig. 36; Hupe, 1857:79, pl. 15, fig. 2; Sowerby, 1869, pl. 5, fig. 2.
  • Tellina alata Linneaeus, 1???

  • Linneaeus 1???: Type locality: ???; Gray 1847:197.
  • Hyria avicularis Lamarck, 1819

  • Lamarck 1819:82??; Type locality: Brazil?; Children 1823:??; Olsson & Wurtz 1951:239.
  • Hyria avicularis var. b. Lamarck, 1819

  • Lamarck, 1819:82.
  • Margarita (Uniosyrmatophorus (Meuschen, 1781)

  • Lea, 1836:2; 1838:13.
  • Margaron (Triquetrasubviridis (Klein, 1753)

  • Lea, 1852:17; 1870:25.
  • Unio syrmatophora (Meuschen, 1781)

  • Deshayes, 1853:219, pl. 29, figs. 10-11.
  • Unio syrmatophorus (Meuschen, 1781)

  • von Martens 1873:210; Ernst, 1876:230.
  • Prisodon syrmataphorus (Meuschen, 1781)

  • Simpson 1900:870; 1914:1218; Baker 1930:63.
  • Prisodon syrmataphorus syrmataphorus (Meuschen, 1781)

  • Haas 1931:43.
  • Prisodon syrmataphorus complanatus (Hupé, 1857)

  • Haas 1931:43.
  • Paxyodon syrmatophorus (Meuschen, 1781)

  • Haas 1966:541.
  • Description: "Shell subtriangular or subtrapeziod, more or less inflated, solid, somewhat inequilateral; beaks full, more or less elevated, apparently without sculpture; posterior ridge high, generally narrowly rounded, often cord-like, occasionally semi-double below, ending at the shells base in a point or a narrow biangulation; dorsal line usually straight, ending in a wing before and behind; anterior end narrowed, cut away and rounded below; base straight or curved; posterior end obliquely or almost squarely truncate, its outline often incurved; surface having delicate striae of growth and fine, radiating lines and sometimes a few folds below the ligament; epidermis shining, greenish, greenish-yellow or brownish, often with metallic tints; teeth elongated, rather solid but compressed; pseudocardinals two or more in each valve; one lateral in the right valve and two in the left, all of them sometimes slightly vertically striate; muscle scars not deep; nacre bluish, flesh-colored or purplish.

    Length 102, height 70, diam. 35 mm. Length 85, height 52, diam. 34 mm." (Simpson, 1914:1218).

    Range: Guiana; Brazil (Simpson, 1900:870).

    Comments: Paxyodon syrmatophorus holds the distinct honor of being the first naiad ever described from South America. Klein (1753) first figured and described asTriquetra subviridis from Guiana and Brazil in 1753. Because Klein was a nonbinomial author his name had to be rejected in favor of Mya syrmatophora Meuschen (1781) (type locality, Guiana). Because of the age of the name and subsequent mis-interpretations on the identity of this species, it has undergone a number of name changes in the past 240 years.

    Specimens Examined: ANSP 125546. (1 specimen, labeled as Triquetra subviridis). Orinoco. USNM 339717 (1). British Guiana. UCM 36453 (1). Lake Fundacion, 20 km E Soledad, on floodplain of the Orinoco River, Anzoategui, Venezuela. 9 October 1988. UCM 36454 (1). Lake Tineo, 15 km E Soledad, on floodplain of the Orinoco River, Anzoategui, Venezuela. 10 November 1988. UCM 36758 (1). Lake Tineo, 15 km E Soledad, on floodplain of the Orinoco River, Anzoategui, Venezuela. 24 September 1988. M. Lasi. INHS 16980 (1). Rio Orinoco, Palmarito, 15 km NE del centro Roblado Marhuanta, cerca de Isla Grande, Bolivar, Venezuela. 4 May 1994. Yomaera Molina de R. One specimen at UCV.

    Literature Cited



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