Modiolus, the horsemussels, are a genus of medium-sized marine bivalve molluscs in the family Mytilidae.
Fossils of species within this very ancient genus can be found in sediments from the Devonian period to recent (age range: 409.1 to 0.0 Ma).
Species within the genus Modiolus include:
Modiolus adriaticus (Lamarck, 1819)
Modiolus albicostus (Lamarck, 1819)
Modiolus americanus (Leach, 1815) - tulip mussel
Modiolus areolatus (Gould, 1850)
Modiolus auriculatus (Krauss, 1848)
Modiolus aurum Osorio Ruiz, 1979
Modiolus barbatus (Linnaeus, 1758) - bearded horsemussel
Modiolus capax (Conrad, 1837) - fat horsemussel
Modiolus carpenteri (Soot-Ryen, 1963) - California horsemussel
Modiolus carvalhoi Klappenbach, 1966
Modiolus cecillii (Philippi, 1847)
Modiolus comptus (G. B. Sowerby III, 1915)
Modiolus demissus
Modiolus eiseni (Strong and Hertlein, 1937) - eisen horsemussel
Modiolus ficoides Macsotay & Campos, 2001
Modiolus gallicus (Dautzenberg, 1895)
Modiolus gubernaculum (Dunker, 1856)
Modiolus kurilensis F. R. Bernard, 1983
Modiolus lulat (Dautzenberg, 1891)
Modiolus margaritaceus (Nomura & Hatai, 1940)
Modiolus matris Pilsbry, 1921
Modiolus modiolus (Linnaeus, 1758) - northern horsemussel
Modiolus modulaides (Röding, 1798)
Modiolus neglectus (Soot-Ryen, 1955) - neglected horsemussel
Modiolus nicklesi Ockelmann, 1983
Modiolus nipponicus (Oyama, 1950)
Modiolus patagonicus (d'Orbigny, 1842)
Modiolus penetectus (Verco, 1907)
Modiolus peronianus Laseron, 1956
Modiolus phaseolinus
Modiolus philippinarum (Hanley, 1843)
Modiolus plumescens (Dunker, 1868)
Modiolus rectus (Conrad, 1837) - straight horsemussel
Modiolus rumphii (Philippi, 1847)
Modiolus sacculifer (S. S. Berry, 1953) - bag horsemussel
Modiolus squamosus Beauperthuy, 1967
Modiolus stultorum (Jousseaume, 1893)
Modiolus traillii (Reeve, 1857)
Modiolus tumbezensis Pilsbry & Olsson, 1935
Modiolus verdensis Cosel, 1995
