Waitakia dorsogibbosa Lin & Steurbaut & Nolf 2024, sp. nov.
Creators: name: Lin, Chien-Hsiang
name: Steurbaut, Etienne
name: Nolf, Dirk
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Percophidae
Waitakia
Waitakia dorsogibbosa

description: Waitakia dorsogibbosa sp. nov.
urn:lsid:zoobank.org:act: 946D0B8E-FDC0-4DA4-8A24-44CBBE0F9BA0
Fig. 9F–G
Diagnosis
OL/OH = 1.4–1.6, OsL/CaL = 0.9–1.1. Trapezoid to triangular otoliths with strong postero-dorsal angle. Anterior and posterior rims pointed. Sulcus well-divided. Ostium wide, arrow-like with low ostial lobe tilting towards antero-ventral rim. Cauda rod-like, horizontal.
Etymology
‘ Dorsogibbosus, a, um ’ = ‘hump bearing on the dorsal part’. Refers to the angulous and humpy dorsal part of the otoliths.
Type material examined
Holotype United States of America • Left otolith; Virginia, Pamunkey River, Hanovertown, Potapaco Member; Fig. 9F; IRSNB P 10755.
Paratype UNITED STATES OF AMERICA • 1 otolith: Fig. 9G; Maryland, Piscataway Creek, Thrift Road ravine, Potapaco Member; IRSNB P 10756.
Type locality and horizon
United States of America, Pamunkey River, Hanovertown (Virginia), Potapaco Member.
Dimensions of the holotype
Length = 2.13 mm; height = 1.37 mm; thickness = 0.55 mm.
Description
This species is characterized by small, trapezoid to triangular otoliths, with dorsal and ventral rims approximately parallel to each other and oblique anterior and posterior rims. The dorsal rim is very short, bears a strong postero-dorsal angle, and its anterior part is inclined downwards. The ventral rim is gently curved and bears an angle at each end. The thickness of the otoliths is most considerable in the middle, with both the inner and outer faces being convex (Fig. 9F 1). The sulcus is well-divided into ostium and cauda, marked by a constriction of the cristae in the central zone of the sulcus. The ostium is wide, arrow-like, with a low ostial lobe expanding ventrally and tilting towards the antero-ventral rim, and its anterior tip nearly reaches the anterior rim of the otolith. The cauda is rod-like, horizontal, and shows a rounded posterior end. There is no trace of a swollen collicular crest on the caudal crista inferior like in gobiids. A dorsal depression is observed above the well-developed caudal crista superior.
Remarks
The otoliths of W. dorsogibbosa sp. nov. resemble most to those of Waitakia beelzebub Lin & Nolf, 2022 from the middle to late Eocene (Lutetian-Bartonian) of the southern USA and other congeners from the Eocene of New Zealand. The thick profile and sulcus morphology are characteristics for assigning the new species to the fossil genus Waitakia. However, W. dorsogibbosa has the shortest dorsal rim exhibiting a triangular outline. The species may represent one of the earliest records of this extinct lineage. It is extremely rare with only two specimens in our material.
Stratigraphic and geographic distribution
Ypresian: Potapaco Member, Virginia and Maryland.
description: Published as part of Lin, Chien-Hsiang, Steurbaut, Etienne & Nolf, Dirk, 2024, Early Eocene fish otoliths from the eastern and southern USA, pp. 203-240 in European Journal of Taxonomy 935 on pages 224-225, DOI: 10.5852/ejt.2024.935.2557, http://zenodo.org/record/11526096