New osteological characteristics identify the first stem sleeper goby (Gobioidei, Odontobutidae) from the Upper Eocene

Amongst Gobioidei, one of the most diverse orders of teleost fishes, the families Odontobutidae (sleeper gobies) and Rhyacichthyidae are considered ‘basal gobioids’ and are therefore particularly interesting for understanding gobioid evolutionary history. However, their fossil record currently consists of only three extinct odontobutid species (two skeleton-based, one otolith-based). The aim of the study associated with this dataset (Bauer et al. 2025 in Papers in Palaeontology) was to investigate the possible relationship of one of the oldest known gobioid fossils, †Paralates chapelcornerensis from the Upper Eocene of southern England, to these families. To achieve this, osteological differences between Odontobutidae and Rhyacichthyidae were newly investigated using 19 extant species from museum collections. This taxon set included both genera of the Rhyacichthyidae, five genera of the Odontobutidae (including Terateleotris; representing 78% of all odontobutid genera), one genus of the..., Study of fossil material

The fossil material included 51 articulated fossils, > 100 isolated bones and four isolated otoliths of †Paralates from the Upper Eocene of the Chapelcorner Fish Bed (Chale, Isle of Wight, UK). The fossil material was studied and photographed under a Leica M165 C microscope equipped with a Jenoptik Gryphax Naos microscope camera. Photos were edited in Photoshop CS6 and Krita. The corresponding figures were prepared with Photoshop CS6 and Inkscape.

Study of recent comparative material

A total of 19 extant species were newly investigated. They encompass:

Apogonidae
Sphaeramia nematoptera (Bleeker 1856)
Apogon imberbis (Linnaeus 1758)

Trichonotidae
Trichonotus arabicus Randall & Tarr 1994
Trichonotus cf. setiger Bloch & Schneider 1801
Trichonotus nikii Clark & von Schmidt 1966

Rhyacichthyidae
Protogobius attiti Watson & Pöllabauer 1998
Rhyacichthys guilberti Dingerkus & Séret 1992
Rhyacichthys aspro (Valenciennes, 1837)

Odontobutidae
M..., , # Data from: New osteological characteristics identify the first stem sleeper goby (Gobioidei, Odontobutidae) from the Upper Eocene

[https://doi.org/10.5061/dryad.7pvmcvf36](https://doi.org/10.5061/dryad.7pvmcvf36)

## Description of the data and file structure

The fossil material and the µCt scans of the extant comparative material were used for osteological study. The focus was study of six bony structures that were well-preserved in the fossil material of †*Paralates*: the first vertebra (atlas), the upper jaw bone (premaxilla), the palatine, the urohyal, the hyoid arch, and the pelvic girdle. These bones were segmented from the µCTs of the extant species and visualized in 3D.

The outcome served to identify structures and character states that differed between Odontobutidae and Rhyacichthyidae. To ensure that characters were consistent between species and capable of distinguishing between genera, three species of *Odontobutis* and three species of *Trichonotus* were included. The...,

在真骨鱼类（teleost fishes）中多样性最高的类群之一𫚥虎亚目（Gobioidei）里，沙塘鳢科（Odontobutidae，俗称眠𫚥虎）与溪鳢科（Rhyacichthyidae）被认为是「基干𫚥虎类」，因此对于阐明𫚥虎类的演化历史具有重要研究价值。然而目前这两个类群的化石记录仅包含3个已绝灭的沙塘鳢科物种：2件基于骨骼化石定名、1件基于耳石（otolith）化石定名。本数据集关联的研究（Bauer等，2025，发表于《古生物学论文集》（Papers in Palaeontology））旨在探讨已知最古老的𫚥虎类化石之一——产自英国南部始新世上层的†Paralates chapelcornerensis与这两个科的系统发育关系。

为达成该研究目标，研究团队基于博物馆馆藏的19个现生物种，重新分析了沙塘鳢科与溪鳢科之间的骨骼形态差异。本次采样的类群涵盖溪鳢科的全部2个属、沙塘鳢科的5个属（包括Terateleotris，覆盖了所有沙塘鳢科属级类群的78%），以及...类群。

### 化石标本研究
本次研究的化石标本包含产自英国怀特岛查尔地区查尔科纳鱼层（Chapelcorner Fish Bed）始新世上层的51件关联保存的†Paralates化石、100余件分离骨骼标本以及4件分离的耳石化石。所有化石标本均在配备Jenoptik Gryphax Naos显微相机的Leica M165 C体视显微镜下进行观察与拍摄，照片使用Photoshop CS6与Krita进行后期编辑，最终图版则通过Photoshop CS6与Inkscape完成制作。

### 现生对比材料研究
本次研究共新分析了19个现生物种，涵盖类群如下：
1. 天竺鲷科（Apogonidae）：
- 斑点拟天竺鲷（Sphaeramia nematoptera，Bleeker 1856）
- 赤天竺鲷（Apogon imberbis，Linnaeus 1758）
2. 毛背鱼科（Trichonotidae）：
- 阿拉伯毛背鱼（Trichonotus arabicus，Randall & Tarr 1994）
- 具棘毛背鱼近似种（Trichonotus cf. setiger，Bloch & Schneider 1801）
- 尼基毛背鱼（Trichonotus nikii，Clark & von Schmidt 1966）
3. 溪鳢科（Rhyacichthyidae）：
- 原溪鳢（Protogobius attiti，Watson & Pöllabauer 1998）
- 吉氏溪鳢（Rhyacichthys guilberti，Dingerkus & Sérét 1992）
- 溪鳢（Rhyacichthys aspro，Valenciennes, 1837）
4. 沙塘鳢科（Odontobutidae）：
- M...,

### 数据来源：《新骨骼形态特征鉴定出首个产自始新世上层的基干眠𫚥虎（𫚥虎亚目，沙塘鳢科）》
https://doi.org/10.5061/dryad.7pvmcvf36

### 数据与文件结构说明
本研究结合了化石标本与现生对比材料的显微CT（µCt）扫描数据开展骨骼形态学研究，重点关注了†Paralates化石标本中保存完好的6处骨骼结构：第一椎骨（寰椎）、上颌骨（前颌骨，premaxilla）、腭骨（palatine）、尾舌骨（urohyal）、舌弓（hyoid arch）以及骨盆带（pelvic girdle）。研究团队从现生物种的显微CT扫描数据中分割出上述骨骼结构并进行三维可视化。
本研究的结果用于识别沙塘鳢科与溪鳢科之间的形态结构与性状状态差异。为确保性状在物种间具有一致性且可用于区分属级类群，研究团队纳入了3个沙塘鳢属（Odontobutis）物种与3个毛背鱼属（Trichonotus）物种作为补充类群。