Gonorynchus abbreviatus Temminck & Schlegel, 1846

Van Hinsbergh, Victor W. M. & Helwerda, Renate A., 2019, Fish Otoliths from the Cabarruyan Piacenzian-Gelasian fauna found in the Philippines, Zootaxa 4563 (3), pp. 401-443 : 404

Gonorynchus abbreviatus Temminck & Schlegel, 1846

(Figure 6)

2012 Gonorynchus abbreviatus Lin CH, Chang CW, p. 72, plate 4

2013 Gonorynchus abbreviatus Nolf D , plate 35

Material: 1 specimen in total. Roxas (1) RGM 962097.

One spindle-shaped otolith (OL:OH= 1.90) is available that has a strong bluntly pointed rostrum and a similarly pointed posterior end. The anterior parts of the dorsal and ventral rims are regularly bent, while their posterior parts run in an almost straight line towards the pointed end. The shallow excisural notch is bordered by the strong blunt rostrum and a shorter antirostrum. The inner surface is convex, in particular its ventral and postdorsal parts. Most characteristic is the sulcus, which consists of a spatula shaped ostium and a cauda that vanishes in a depression between the elevated postdorsal and ventral parts. It is bordered by a short crista superior that is strongly developed at the transition between ostium and cauda, and a strong crista inferior that consists of two parts, one in a straight line along the ostium and first part of the cauda, and a second part that runs along the posterior part of the cauda obliquely in ventro-posterior direction. A deep ventral furrow is present. A dorsal field is mainly marked by the crista superior. The outer surface of the otolith is convex in all directions.

The otolith has a high resemblance to otoliths of Gonorynchus and Notogoneus . The later regards a fossil genus that is encountered as a fresh/brackish water fish in Germany, which displays considerable outline variation ( Weiler, 1963). Several recent Gonorynchus species are known today, most of them in Australia or Hawaii. One species, Gonorynchus abbreviatus Temminck & Schlegel, 1846 , is encountered in Taiwan and Japan (depicted in Nolf, 2013, plate 35 together with G. greyi ). The otolith presented here has good resemblance to G. abbreviatus in important aspects, but more specimens should be available to verify whether the present specimen fits within the outline variation of G. abbreviatus .