Morphological structures of the shell of Mytilus trossulus and Crenomytilus grayanus in early ontogenesis and their importance in the taxonomy of Mytilinae (Bivalvia: Mytilidae)

Abstract

The morphostructures of larval and juvenile shells of two common species of bivalves of the north-western Sea of Japan, Mytilus trossulus and Crenomytilus grayanus have been examinated. Two types of morphological features were identified on the basis of the results obtained and comparison with materials of other species of the subfamily Mytilinae. One group of morphological features (absence or presence of the nepioconch; form and size of posterior lateral teeth) characterizes the higher taxonomic categories, while the other one (morphological details of general outline of the secondary prodissoconch and juvenile shell; ratio shell height/length; form, size and number of provincular and additional teeth; number of posterior lateral teeth, and others) serves to separate taxa of the generic or specific ranks.

Morphology of larvae of the family Mytilidae (Bivalvia) from the north-western part of the Sea of Japan

“…Adula falcatoides Habe 1955 Kasyanov et al, 1983;Kulikova & Kolotukhina, 1989;Evseev, 2005 Crenomytilus grayanus (Dunker 1853) Drozdov & Kulikova, 1979;Kasyanov et al, 1983;Kulikova & Kolotukhina, 1989;Kalashnikova & Aizdaicher, 1993;Evseev et al, 2006Modiolus kurilensis Bernard 1983Kulikova & Kolotukhina, 1989Kasyanov et al, 1998;Evseev et al, 2005 Musculista senhousia (Benson in Cantor 1842) Kulikova, 1978;Tanaka, 1979b;Kasyanov et al, 1983;Kulikova & Kolotukhina, 1989;Sakai & Sekiguchi, 1992;Kimura & Sekiguchi, 1994 Mytilus coruscus Gould 1861 Tanaka, 1979a;Hur & Hur, 2000;Semenikhina & Kolotukhina, 2001 Mytilus galloprovincialis Lamarck 1819 Le Pennec & Masson, 1976;Zakhvatkina, 1972 Mytilus trossulus Gould 1850 Kasyanov et al, 1983;Kulikova & Kolotukhina, 1989;Evseev et al, 2006 mytilids both ends are rounded and the anterior end is more obtuse. The ventral margin is mostly rounded but in some species it is almost straight.…”

Treatise Online no. 61: Part N, Revised, Volume 1, Chapter 4: The early shell: Ontogeny, features, and evolution

“…Despite this early start, and perhaps excluding the special interest in the postlarval ontogeny of heterodont teeth, systematic studies of the earliest developmental stages of hinges have been relatively rare. raMoriNo & caMPos, 1979;caMPos & raMoriNo, 1980;siddall, 1980;raMoriNo & caMPos, 1983;kiMura & sekiGuchi, 1994;ockelMaNN, 1995;ozaWa & sekiGuchi, 2002;okutaNi, FuJikura, & sasaki, 2003;ockelMaNN, & diNeseN, 2009), culminating in the detailed studies by evseev and co-workers (evseev, seMeNikhiNa, & kolotukhiNa, 2004a, 2005seMeNikhiNa, kolotukhiNa, & evseev, 2008;evseev, kolotukhiNa, & kulikova, 2011). Mytilids display the most stages of earlyhinge development of all bivalves hitherto studied, in a surprisingly complex series.…”