Mataichthys procerus 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 : 342-344

Mataichthys procerus Schwarzhans sp. nov.

Fig. 13P–V.

Etymology: From Latin procerus , high−bodied, referring to the high−bodied shape of the otolith.

Type material: Holotype: NMNZ S.52735 ( Fig. 13P) . Paratypes: 23 specimens (7 specimens NMNZ S.52736, same location as holotype, HH4 bed; 7 specimens, NMNZ S.52737, same location as holotype, HH1a bed; 6 specimens NMNZ S.52738, same location as holotype, HH1d bed; 3 specimens NMNZ S.52739, Vinegar Hill, site 2) ( Fig. 13Q–V) .

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

Type horizon: HH4 bed, Bannockburn Formation, early Miocene.

Other material.— 444 specimens: 7 specimens, same location as holotype, HH4 ; 9 specimens, HH1b; 398 specimens, HH1a; 5 specimens, Vinegar Hill, site 1; 25 specimens, Vinegar Hill, site 2.

Diagnosis.—OL:OH = 1.0– 1.2 in specimens longer than 3 mm. Anterior−ventral and posterior−ventral projections feeble or absent. Dorsal rim high, regularly rounded.

Description.—Robust, compressed, high−bodied otoliths up to about 5.5 mm long. OH:OT = 3.0–3.4. No or very feeble anterior−ventral projection, indistinct to moderately developed posterior−ventral projection. Dorsal rim high, regularly rounded. Ventral rim nearly straight, horizontal. Anterior

Q– S. Mataichthys sp. , deformed specimens, Manuherikia River, HH 1a. Q, S. Probably of Mataichthys bictenatus Schwarzhans, Scofield, Tennyson, and T. Worthy gen. et sp. nov. Q. NMNZ S.52747a, anterior view (Q 1), inner face (Q 2), ventral view (Q 3). S. NMNZ S52747c, inner face (S 1), posterior view (S 2). R. Probably of Mataichthys procerus Schwarzhans sp. nov., NMNZ S.52747b, inner face.

http://dx.doi.org/10.4202/app.2010.0127

and posterior rims blunt, slightly inclined, straight. Rims irregularly undulating, crenulated in juveniles.

Inner face nearly flat, with somewhat rugged surface. Sulcus with median position, moderately large and deepened, typical shoe−sole shape, slightly inclined. OL:SuL 1.6–1.8. Dorsal field high, with mostly well marked dorsal depression. Ventral field narrower, somewhat elevated, with distinct ventral furrow at moderate distance from ventral rim.

Outer face slightly convex with small precentral umbo, irregularly ornamented or smooth.

Remarks.—Otoliths of M. procerus are the second most common eleotrid species in the Bannockburn Formation after M. bictenatus with which it occurs. The main differences are the more compressed shape with the lower index OL:OH (1.0–1.2 versus 1.3–1.5) in adults (larger than 3 mm, not apparent in smaller specimens) and the much less pronounced anterior−ventral and posterior−ventral projections. Small specimens below 2 mm long may not always be distinguishable because the index OL:OH of both species converge as a result of allometric ontogenetic growth in M. bictenatus leaving the shape of the ventral and posterior rims the only useful distinguishing characters.

As for M. bictenatus , a few altered/deformed otoliths with thickened inner faces and deepened sulci have also been observed in M. procerus . One such specimen tentatively attributed to M. procerus is shown in Fig. 14R.

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