Modiolus

Horse mussel Modiolus modiolus, from Kåre Telnes.

Belongs within: Mytilidae.

Modiolus is a genus of mussels generally regarded as dating from the Devonian to the present day, though some have suggested that the name should be restricted to Caenozoic forms (Hodges 2000). Modiolus species commonly bear a hairy external covering derived from the periostracum, the organic outer layer of the shell. Living species commonly form dense clumps or beds either partially buried in sediment or attached to hard substrata. The northern horsemussel M. modiolus is found in cooler waters of the northern Atlantic. The late Triassic to middle Jurassic (Rhaetian–Bajocian) subgenus Cyranus differs from the type genus in having a straighter, narrower shell that is more elongated posteriorly (Hodges 2000).

Characters (from Hodges 2000): Shell equivalve, elongated posteriorly; umbones placed just behind anterior end, never terminal; ligament long; ornament of commarginal striae or smooth; periostracum generally hirsute.

<==Modiolus Lamarck 1799 (see below for synonymy) H00
    |--M. (Modiolus) H00
    |    |--*M. (M.) modiolus (Linnaeus 1758) H00 [=Mytilus modiolus H00; incl. Modiola papuana J64]
    |    |--M. (M.) laevis Sowerby 1812 (n. d.) H00
    |    `--M. (M.) minimus (Sowerby 1818) (see below for synonymy) H00
    `--M. (Cyranus Hodges 2000) H00
         |--M. (*C.) hillanus (Sowerby 1818) (see below for synonymy) H00
         |--M. (C.) scalprum H00
         |--M. (C.) sowerbyanus H00
         `--M. (C.) ventricosus (Roemer 1836) (see below for synonymy) H00

Modiolus incertae sedis:
  M. adriaticus M62
  ‘Modiola’ albicostata H79
  M. altijugatus M49
  M. americanus M63
  ‘Mytilus’ arborescens Chemnitz 1795 [=Modiola arborescens] H09
  M. arcuatulus Hanley 1843 BD86
  M. areolatus (Gould 1850) P61
  M. auriculatus Krauss 1848 BD86 [=Modiola auriculata H09]
  ‘Modiola’ australis Gray 1827 H09
  ‘Modiola’ braziliensis C64
  ‘Modiola’ capax C64
  M. confusus [=Perna confusa] F26
  ‘Modiola’ contracta Conrad 1855 C64
  ‘Modiola’ crassissima M’Coy 1847 F71
  M. demissus ATW84
  M. difficilis KBC03
  ‘Modiola’ dunlopensis Etheridge 1902 F71
  M. elongata (Swainson 1821) XZ10
  M. flavida Dunker 1856 MG-H11
  M. fluviatilis (Hutton 1878) P61
  ‘Modiola’ fornicata Carpenter 1864 C64
  M. glaberrimus (Dunker 1856) BD86
  M. kurilensis PV06
  ‘Modiola’ lignea Reeve 1858 H09
  ‘Modiola’ lonsdalei B89
  ‘Modiola’ marmorata C64
  M. metcalfei (Hanley 1844) XZ10
  ‘Modiola’ modiclaeoidea G31
  ‘Modiola’ mytiliformis Etheridge 1917 F71
  M. neozelanicus (Iredale 1915) P61
  ‘Modiola’ nitens [incl. M. subpurpureus] C64
  M. pallidulus B56
  ‘Modiola’ philippinarum Hanley 1844 H09
  M. politus PP64
  M. proclivis Iredale 1939 MG-H11
  M. pulex M54 [incl. M. ater (Zelebor 1866) (preoc.) F26]
  ‘Modiola’ recta [incl. Mo. flabellata, Mytilus (Modiola) flabellatus] C64
  ‘Modiola’ semifusca C64
  ‘Modiola’ striatula G88
  ‘Modiola’ vulgaris S18
  ‘Modiola’ yunnanensis G31

Modiolus Lamarck 1799 [incl. Eumodiolus Ihering 1900, Modiola Lamarck 1801, Nudiola Monterosato 1917, Volsella Scopoli 1777 (nom. rej.)] H00

Modiolus (*Cyranus) hillanus (Sowerby 1818) [=Modiola hillana, Mytilus (Modiolus) hillanus, Volsella hillana; incl. V. langportensis var. angustiformis Richardson & Tutcher 1914, V. langportensis var. erecta Richardson & Tutcher 1914, Modiola glabrata Dunker 1846, Mytilus glabratus, V. langportensis Richardson & Tutcher 1914, My. stoppanii Dumortier 1864, Modiola stoppanii] H00

Modiolus (Cyranus) ventricosus (Roemer 1836) [=Modiola ventricosa; incl. Modiola elongata Koch & Dunker 1837 non (Swainson 1821), Mytilus geuxii d’Orbigny 1849, Myt. hillanus Goldfuss 1837 non Modiola hillana Sowerby 1818, Myt. liasinus Terquem 1855, Volsella liasina, Myt. morrisi Oppel 1856, Modiola nitidula Dunker 1846, Myt. (Modiolus) nitidulus, Modiola numismalis Oppel 1854, Myt. (Modiolus) numismalis, Myt. productus Terquem 1855, Modiola psilonoti Quenstedt 1856, Myt. rusticus Terquem 1855, Modiola rustica, Myt. scalprum Goldfuss 1837, Myt. simoni Terquem 1855, Myoconcha spatula d’Orbigny 1849, Myt. thiollierei Dumortier 1869] H00

Modiolus (Modiolus) minimus (Sowerby 1818) [=Modiola minima, Mytilus minimus, Mitylus (l. c.) minimus, Volsella minima; incl. Modiola minimus Goldfuss 1837, V. wickesi Richardson & Tutcher 1914] H00

*Type species of generic name indicated

REFERENCES

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[B89] Boehm, G. 1889. Ein Beitrag zur Kenntniss fossiler Ophiuren. Berichte der Naturforschenden Gesellschaft zu Freiburg I. B. 4: 232–287, pls 4–5.

[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.

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[KBC03] Kashin, I. A., E. V. Bagaveeva & S. F. Chaplygina. 2003. Fouling communities of hydrotechnical constructions in Nakhodka Bay (Sea of Japan). Russian Journal of Marine Biology 29: 267–283.

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[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O’Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[M63] Merrill, A. S. 1963. Mollusks from a buoy off Georgia. Nautilus 77 (2): 68–70.

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[PV06] Pimenova, E. A., & A. A. Varaksin. 2006. Putative nitroxidergic cells in the digestive system of some mytilids (Mollusca: Bivalvia: Mytilidae) revealed by NADPH-diaphorase histochemistry. Malacologia 49 (1): 61–77.

[P61] Powell, A. W. B. 1961. Shells of New Zealand: An illustrated handbook 4^th ed. Whitcombe and Tombs Limited: Christchurch.

[S18] Sars, G. O. 1918. An Account of the Crustacea of Norway with short descriptions and figures of all the species vol. 6. Copepoda. Cyclopoida pts 11–12. Lichomolgidae (concluded), Oncaeidae, Corycaeidae, Ergasilidae, Clausiidae, Eunicicolidae, supplement. Bergen Museum: Bergen.

[XZ10] Xu, F., & J. Zhang. 2010. Study on the bivalve faunal composition of the Yellow Sea and Bohai Sea. In: China-Russia Bilateral Symposium: Proceedings of the China-Russia Bilateral Symposium of "Comparison on Marine Biodiversity in the Northwest Pacific Ocean", 10–11 October 2010, Qingdao (China) pp. 7–12. Institute of Oceanology, Chinese Academy of Sciences; A. V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences.

Last updated: 6 March 2022.