. Bonner zoologische Monographien. Zoology. 72 In the outgroups, the nasal bone is narrow and elongated, and located over the meseth- moid and lateral ethmoid; the nasal portion of the supraorbital canal is not interrupted. Preethmoid (, B). In cyprinids, the paired preethmoid is located between the anteroventral side of the mesethmoid and anterolateral side of the vomer. Ramaswami (1955a) stated that Phoxinus lacks the preethmoid. This is not the case in the specimens of Phoxinus I studied. All species of Phoxinus have the preethmoid. In Phoxinus, the preethmoid is semi-spherical in sh
. Bonner zoologische Monographien. Zoology. 72 In the outgroups, the nasal bone is narrow and elongated, and located over the meseth- moid and lateral ethmoid; the nasal portion of the supraorbital canal is not interrupted. Preethmoid (, B). In cyprinids, the paired preethmoid is located between the anteroventral side of the mesethmoid and anterolateral side of the vomer. Ramaswami (1955a) stated that Phoxinus lacks the preethmoid. This is not the case in the specimens of Phoxinus I studied. All species of Phoxinus have the preethmoid. In Phoxinus, the preethmoid is semi-spherical in shape. Its position in the skull is similar to that in other cyprinids. The variations of the preethmoid among Phoxinus species is in its relative size. The preethmoid is well-developed and large in P. phoxinus (TS 47[1]). It is smaller, not well-developed in other species of Phoxinus and in the outgroups (TS Mesethmoid (, 39A-B). In cyprinids, the mesethmoid is an endochondral single bone resting on a cartilage (planum ethmoidale) on the vomer, and located at the ventral side of the supraethmoid (Mayden 1989). In Phoxinus, the planum ethmoidale is observed in a 33 mm standard length specimen of P. eos (). The cartilage is re- duced or absent in larger specimens. Dorsally and anteriorly, the mesethmoid shares su- tures with the posterior side of the supraethmoid (). The mesethmoid sutures with the lateral ethmoid posteriorly. The mesethmoid is irregular in shape. Anterolaterally, the bone bears two foramina for nerves (). Anteriorly, the mesethmoid is concave; the anterior surface of the mesethmoid sutures with the posterior surface of the supraethmoid. Ventrally, the mes- ethmoid bears one or two conea (Gasowska 1979), the anterior and posterior ones, which are concave and position at the ventral side of the mesethmoid (). Variation in the mesethmoid of Phoxinus occurs mainly at its ventral aspect. In P. phoxi- nus, neogaeus, and eos,
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