Neurosensory evolution in thalattosuchian crocodylomorphs – integrating somatosensory and visual adaptations across ecological transitions

Journal article

Thalattosuchians, an extinct lineage of Mesozoic crocodylomorphs, underwent a remarkable evolutionary transition from primarily semi-aquatic teleosaurids, through increasingly ocean-adapted metriorhynchoids, to the fully pelagic metriorhynchids. Understanding how such a major habitat shift affected their sensory systems provides valuable perspective on vertebrate adaptations. Here, we present a comparative analysis integrating digital endocranial reconstructions from computed tomography (CT) scans of 22 skulls of crocodylomorph species, including extant crocodylians and a diverse range of thalattosuchians. Focusing on somatosensation and vision, we seek to gain new insights into sensory evolution in the group using statistical comparative methods. Our findings reveal that thalattosuchians, especially pelagic metriorhynchids, evolved significantly smaller trigeminal ganglia relative to skull size than non-marine crocodylomorphs, suggesting reduced investment in facial mechanoreception. Interestingly, visual structures (orbit and optic nerve canal dimensions) scale proportionally with skull size across thalattosuchians, reflecting proportional scaling rather than enlargement. This pattern suggests that metriorhynchids maintained visual reliance and any functional enhancement was likely achieved through optical or neural optimisation rather than cranial modification. These findings challenge assumptions of uniform sensory trade-off during aquatic transitions and highlight the importance of lineage-specific constraints in shaping evolutionary trajectories.

Authors: Soni, A; Young, MT; Bowman, CIW; Erb, A; Schwab, JA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Taylor & Francis
• Journal: Historical Biology
• Publication date: 2026-04-08
• Acceptance date: 2026-03-18
• DOI: 10.1080/08912963.2026.2650482
• EISSN: 1029-2381
• ISSN: 0891-2963
• Language: English
• Keywords: endocranial anatomy; macroevolution; Metriorhynchidae; Thalattosuchia; crocodylomorpha