. Bulletin. Science; Natural history; Natural history. RESEARCH NOTES 65. Fig. 3. Left sagittae of fish genera belonging to family Neoscopelidae (otolith lengths and fish standard lengths in mm are noted): a) Solivomer arenidens (, 76); b) Neoscopelus sp. (, 150); c) Scopelengys tristis (, 172); d) Neoscopelus sp. (, 37). Outline of sulcus has been indicated with broken, inked-in line. In using otoliths (sagittae) as a taxonomic character, the most important feature for determining family relationships (and ancestry) is the sulcus (groove on the inner face): its position, configura
. Bulletin. Science; Natural history; Natural history. RESEARCH NOTES 65. Fig. 3. Left sagittae of fish genera belonging to family Neoscopelidae (otolith lengths and fish standard lengths in mm are noted): a) Solivomer arenidens (, 76); b) Neoscopelus sp. (, 150); c) Scopelengys tristis (, 172); d) Neoscopelus sp. (, 37). Outline of sulcus has been indicated with broken, inked-in line. In using otoliths (sagittae) as a taxonomic character, the most important feature for determining family relationships (and ancestry) is the sulcus (groove on the inner face): its position, configuration and differentiation. Although, in the Ce- tomimidae the sulcus is slightly excavated, it appears to be a slightly raised "blip" in the center of the otolith; it opens to the margin anterodorsally via a presulcal trough. Ostium (anterior part of sulcus) and cauda (posterior part) are undiffer- entiated. In Gyrinomimus, Cetomimus and Ditropichthys (Figs, lb, c and f), the otolith has smoothly rounded margins, and appears trilobate in outline. The sulcus is encircled by a low, smooth ridge except at the point of entry for the presulcal trough. In Cetostomus (Fig. le), the otolith margin is roughened, and the sulcus is rimmed by a high, relatively sharp ridge, somewhat foliose in appearance. Otolith length in all four genera is equal to or slightly greater than otolith height. In Rondeletia (Fig. Id, Rondeletiidae), the sulcus is slightly excavated, circular in outline, and surrounded by a slightly raised rim. In contrast with cetomimid otoliths, the sagitta of Rondeletia is much higher than long, and the sulcus lies just inside the anterior margin. A very short presulcal trough leads to the margin, and as with cetomimid otoliths, ostium and cauda cannot be distinguished. In Barbourisia (Fig. la, Barbourisiidae) the sulcus is elongate and deeply ex- cavated. It is surrounded by a high, broadly rounded rim, and as in the other two. Please note that these images are ex
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