Galaxias angustiventris Schwarzhans, 2012

Schwarzhans, Werner, Scofield, R. Paul, Tennyson, Alan J. D., Worthy, Jennifer P. & Worthy, Trevor H., 2012, Fish remains, mostly otoliths, from the non-marine early Miocene of Otago, New Zealand, Acta Palaeontologica Polonica 57 (2), pp. 319-350 : 324-326

Galaxias angustiventris Schwarzhans sp. nov.

Fig. 4F–H.

Etymology: From Latin angustus, narrow and venter, belly; referring to the narrow ventral field on the inner face below the sulcus.

Type material: Holotype: NMNZ S.52707 ( Fig. 4F) . Paratypes: three specimens, NMNZ S.52708 ( Fig. 4G, H) .

Type locality: Home Hills Station, Manuherikia River near St Bathans , Otago .

Type horizon: HH1a bed, Bannockburn Formation, early Miocene.

Diagnosis.—Oval outline with regularly rounded dorsal and posterior rims. Ventral rim shallow. Rostrum short, sharp; excisura sharp, moderately wide. Ostium narrow; cauda terminating far from posterior tip of otolith. Ventral field on in−

F–H. Galaxias angustiventris Schwarzhans sp. nov. F. Holotype, NMNZ S.52707, early Miocene, Bannockburn Formation, Manuherikia River, HH 1a, outer face (F 1), inner face (F 2), dorsal (F 3), ventral (F 4), posterior (F 5), and anterior (F 6) views. G. Paratype, NMNZ S.52708a, inner face, early Miocene, Bannockburn Formation, Manuherikia River, HH 1a. H. Paratype, NMNZ S.52708b, inner face, early Miocene, Bannockburn Formation, Manuherikia River, HH 1a. I–J. Galaxias brevicauda Schwarzhans sp. nov. I. Holotype, NMNZ S.52709 early Miocene, Bannockburn Formation, Manuherikia River, HH 1a, outer face (I 1), inner face (I 2), anterior (I 3), ventral (I 4), and dorsal (I 5) views. J. Paratype, NMNZ S.52710, early Miocene, Bannockburn Formation, Manuherikia River, HH 1a, anterior view (J 1), ventral view (J 2), inner face (J 3).

ner face narrow with distinct furrows below sulcus and close to rim of otolith.

Description.—Moderately compressed otoliths with regularly rounded outline except for shallow ventral rim and small, but sharply pointed rostrum. Size up to 4.5 mm. Excisura sharp, short; antirostrum short, broad. Dorsal rim occasionally undulating. OL:OH = 1.3–1.4; OH:OT about 3.2.

Inner face slightly convex with short, narrow, slightly deepened, inferior sulcus. Ostium narrow, anteriorly open, deeper than cauda; cauda straight, terminating far from posterior tip of otolith. OL:SuL about 1.5; CaL:OsL about 1.0. Dorsal field wide, often somewhat irregularly ornamented, with broad but indistinct depression. Ventral field narrow, with furrow below sulcus and furrow close to ventral rim.

Outer face flat with several short radial furrows on dorsal field and occasional few very short furrows along ventral rim of otolith.

Remarks.— Galaxias angustiventris is similar to G. brevicauda Schwarzhans sp. nov. with both species having otoliths with a short cauda terminating far from the posterior tip of the otolith. It differs from the latter mainly in the rounded dorsal rim, the large dorsal field and narrow ventral field, the short rostrum, the wide excisura, the presence of a ventral furrow close to the ventral rim of the otolith and the slightly more thick appearance (OH:OT about 3.2 versus 3.8).

None of the otoliths known from the living species of the genus shows a similarly short cauda (for comparison see Fig. 4A–E). It is therefore possible that the two species represent an extinct genus of the family Galaxiidae .

Stratigraphic and geographic range.—Bannockburn Formation, Manuherikia River.