Orbit orientation in didelphid marsupials (Didelphimorphia: Didelphidae)

Pilatti, Patricia; Astúa, Diego

doi:10.1093/cz/zow068

Cited by 5 publications

(7 citation statements)

References 65 publications

(98 reference statements)

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“…As expected, NT sparassodonts analyzed for this study exhibit high orbital convergence, a characteristic feature of extant felids and hyaenids. Among extant marsupials, orbital orientation parameters in NT sparassodonts are similar to those found in non-caluromyine didelphids (high convergence and low verticality angle; 3 , 12 ), although the former show slightly lower values for verticality (Fig. 2a ).…”

Section: Discussionsupporting

confidence: 62%

“…S1 and Table S2 ). Previous methods vary in their choice of landmarks 11 , 12 , 27 , 28 . Heesy’s method 11 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“… 36 ). Alternatively, differences among sparassodont families might reflect the effect of snout proportions on orbital orientation 12 . However, in this scenario borhyaenids would be expected to display higher convergence values than hathliacynids, which is not the case.…”

Section: Discussionmentioning

confidence: 99%

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Seeing through the eyes of the sabertooth Thylacosmilus atrox (Metatheria, Sparassodonta)

2023

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The evolution of mammalian vision is difficult to study because the actual receptor organs—the eyes—are not preserved in the fossil record. Orbital orientation and size are the traditional proxies for inferring aspects of ocular function, such as stereoscopy. Adaptations for good stereopsis have evolved in living predaceous mammals, and it is reasonable to infer that fossil representatives would follow the same pattern. This applies to the sparassodonts, an extinct group of South American hypercarnivores related to marsupials, with one exception. In the sabertooth Thylacosmilus atrox, the bony orbits were notably divergent, like those of a cow or a horse, and thus radically differing from conditions in any other known mammalian predator. Orbital convergence alone, however, does not determine presence of stereopsis; frontation and verticality of the orbits also play a role. We show that the orbits of Thylacosmilus were frontated and verticalized in a way that favored some degree of stereopsis and compensated for limited convergence in orbital orientation. The forcing function behind these morphological tradeoffs was the extraordinary growth of its rootless canines, which affected skull shape in Thylacosmilus in numerous ways, including relative orbital displacement.

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Section: Discussionsupporting

confidence: 62%

“…S1 and Table S2 ). Previous methods vary in their choice of landmarks 11 , 12 , 27 , 28 . Heesy’s method 11 (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Seeing through the eyes of the sabertooth Thylacosmilus atrox (Metatheria, Sparassodonta)

2023

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“…Histology slides were photographed on a Zeiss AxioScan seven and immunofluorescent sections on a Zeiss AxioZoom, Apotome or LSM800-Airyscan microscope equipped with Zen software (v2.3 or 3.0). Centroid size of crania was quantified in ImageJ by delimiting the shape above a virtual line from the upper jaw to earlobe to occiput in the sagittal plane ( Pilatti and Astúa, 2017 ).…”

Section: Methodsmentioning

confidence: 99%

Multiple congenital malformations arise from somatic mosaicism for constitutively active Pik3ca signaling

Maréchal

Poliard

Henry

et al. 2022

Front. Cell Dev. Biol.

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Recurrent missense mutations of the PIK3CA oncogene are among the most frequent drivers of human cancers. These often lead to constitutive activation of its product p110α, a phosphatidylinositol 3-kinase (PI3K) catalytic subunit. In addition to causing a broad range of cancers, the H1047R mutation is also found in affected tissues of a distinct set of congenital tumors and malformations. Collectively termed PIK3CA-related disorders (PRDs), these lead to overgrowth of brain, adipose, connective and musculoskeletal tissues and/or blood and lymphatic vessel components. Vascular malformations are frequently observed in PRD, due to cell-autonomous activation of PI3K signaling within endothelial cells. These, like most muscle, connective tissue and bone, are derived from the embryonic mesoderm. However, important organ systems affected in PRDs are neuroectodermal derivatives. To further examine their development, we drove the most common post-zygotic activating mutation of Pik3ca in neural crest and related embryonic lineages. Outcomes included macrocephaly, cleft secondary palate and more subtle skull anomalies. Surprisingly, Pik3ca-mutant subpopulations of neural crest origin were also associated with widespread cephalic vascular anomalies. Mesectodermal neural crest is a major source of non-endothelial connective tissue in the head, but not the body. To examine the response of vascular connective tissues of the body to constitutive Pik3ca activity during development, we expressed the mutation by way of an Egr2 (Krox20) Cre driver. Lineage tracing led us to observe new lineages that had normally once expressed Krox20 and that may be co-opted in pathogenesis, including vascular pericytes and perimysial fibroblasts. Finally, Schwann cell precursors having transcribed either Krox20 or Sox10 and induced to express constitutively active PI3K were associated with vascular and other tumors. These murine phenotypes may aid discovery of new candidate human PRDs affecting craniofacial and vascular smooth muscle development as well as the reciprocal paracrine signaling mechanisms leading to tissue overgrowth.

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“…Histology and in situ hybridization slides were photographed on a Zeiss AxioScan 7 and immunofluorescent sections on a Zeiss AxioZoom, Apotome or LSM800-Airyscan microscope equipped with Zen software (v2.3 or 3.0). Centroid size of crania was quantified in ImageJ by delimiting the shape above a virtual line from the upper jaw to earlobe to occiput in the sagittal plane (Pilatti and Astúa, 2017).…”

Section: Methodsmentioning

confidence: 99%

Multiple congenital malformations arise from somatic mosaicism for constitutively active Pik3ca signaling

Maréchal

Poliard

Moreno

et al. 2022

Preprint

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1AbstractRecurrent missense mutations of the PIK3CA oncogene are among the most frequent drivers of human cancers. These often lead to constitutive activation of its product p110α, a phosphatidylinositol 3-kinase (PI3K) catalytic subunit. In addition to causing a range of rare and common cancers, the H1047R mutation is also found in affected tissues of a distinct set of congenital tumours and malformations. Collectively termed PIK3CA-related disorders (PRDs), these lead to overgrowth of skin, brain, adipose, connective, musculoskeletal tissues and/or blood and lymphatic vessel components. Vascular malformations are frequently observed in PRD due to cell-autonomous activation of the PI3K signaling pathway within endothelial cells. These, like most muscle, connective tissue and bone, are derived from the embryonic mesoderm. However, important organ systems affected in PRDs are neuroectodermal derivatives. To further examine their development, we drove the most common post-zygotic activating mutation of Pik3ca in neural crest and related embryonic lineages. Effects in cells having once expressed Wnt1, including the brain roofplate and most neural crest, were most dramatic in the head. Outcomes included megalencephaly, cleft secondary palate and more subtle skull anomalies. Surprisingly, Pik3ca-mutant subpopulations of either mesodermal or neural crest origin was associated with widespread vascular anomalies, leading us to incidentally discover previously undescribed lineages that had expressed the transcription factor Egr2 (Krox20) and that may be co-opted in pathogenesis. Schwann cell precursors having transcribed either Krox20 or Sox10 also gave rise to adult-onset vascular tumors and cancers, including melanoma, after Pik3ca activation. These murine phenotypes may aid discovery of new candidate human PRDs affecting craniofacial and vascular smooth muscle development as well as the reciprocal paracrine signaling mechanisms leading to tissue overgrowth.

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Orbit orientation in didelphid marsupials (Didelphimorphia: Didelphidae)

Cited by 5 publications

References 65 publications

Seeing through the eyes of the sabertooth Thylacosmilus atrox (Metatheria, Sparassodonta)

Seeing through the eyes of the sabertooth Thylacosmilus atrox (Metatheria, Sparassodonta)

Multiple congenital malformations arise from somatic mosaicism for constitutively active Pik3ca signaling

Multiple congenital malformations arise from somatic mosaicism for constitutively active Pik3ca signaling

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