KNM-ER 64061 is a partial skeleton from the upper Burgi Member of the Koobi Fora Formation (2.02–2.06 Ma) associated taphonomically and geochemically with a nearly complete mandibular dentition (KNM-ER 64060) attributed to Homo habilis. The skeleton comprises the clavicle, scapular fragments, both humeri, both ulnae, both radii, and a fragmentary sacrum and os coxae, making this the most complete H. habilis skeleton recovered thus far. The upper limb elements are similar to those of other early Homo specimens. Notably, the humerus is slender with a weakly-projecting lateral epicondyle, a relatively wide capitulum and a narrow trochlea, and the ulna has a relatively large radial notch. Although KNM-ER 64061 does not preserve a lower limb, limited features of the ischium suggest lower limb mechanics more similar to Homo than to australopiths. Brachial index estimates support previous conclusions that H. habilis had a relatively long forearm compared to Homo erectus. All upper limb elements possess strikingly thick cortices, resembling the condition in australopiths and other early Homo fossils. The stature estimate of 160 cm based on humeral length is intermediate between those for H. habilis (OH 62, KNM-ER 3735) and H. erectus (KNM-ER 1808, KNM-WT 15000). The body mass estimate of 30.7–32.7 kg is slightly lower than other H. habilis specimens and noticeably lower than estimates for H. erectus. KNM-ER 64061 indicates that H. habilis retained more primitive proportions and was smaller in stature and mass than H. erectus.
This study reveals novel skeletal deformities in two marine fish species (Nemipterus randalli and Pomadasys stridens) from Antalya Bay, Türkiye, linking them to potential impacts on locomotion and ecological fitness. Major abnormalities include pectoral fin absence, saddleback syndrome, and nasal defects. This study establishes the critical relevance of documenting fish deformities as a powerful and sensitive tool for monitoring ecosystem health. The study advocates for integrating imaging technologies into ecological monitoring to detect hidden stressors affecting marine life. By understanding how deformities influence movement and survival, scientists can better evaluate anthropogenic impacts on fish populations. These insights advance the use of morphological abnormalities as sensitive indicators of ecosystem health, supporting more proactive marine conservation strategies.
Actinopterygii is a major extant vertebrate group, but limited data are available for its earliest members. Here we investigate the morphology of Devonian actinopterygians, focusing on the lower jaw. We use X-ray computed tomography (XCT) to provide comprehensive descriptions of the mandibles of 19 species, which span the whole of the Devonian and represent roughly two-thirds of all taxa known from more than isolated or fragmentary material. Our findings corroborate previous reports in part but reveal considerable new anatomical data and represent the first detailed description for roughly half of these taxa. The mandibles display substantial variation in size, spanning more than an order of magnitude. Although most conform to a generalized pattern of a large dentary and one or two smaller infradentaries, XCT data reveal significant differences in the structure of the jaw and arrangement of teeth that may be of functional relevance. We report the presence of a rudimentary coronoid process in several taxa, contributed to by the dentary and/or infradentaries, as well a raised articular region, resulting in a mandible with an offset bite and that functions as a bent level arm. Among the most striking variation is that of tooth morphology: several taxa have heterodont dentary teeth that vary in size and orientation, and multiple variations on enlarged, whorl-like and posteriorly-oriented anterior coronoid dentition are observed. We use these new data to revise morphological characters that may be of phylogenetic significance and consider the possible functional implicationds of these traits. The observed variation in mandible form and structure suggests previously unappreciated functional diversity among otherwise morphologically homogenous Devonian ray-finned fishes.
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