Systematic Revision of the Northern Short-tailed Shrew, <i>Blarina brevicauda</i> (Say)
Notice bibliographique
Résumé
Short-tailed shrews, genus Blarina, are common inhabitants of a variety of terrestrial habitats in most of eastern North America. Of the 4 species currently recognized, the northern short-tailed shrew, Blarina brevicauda (Say, 1823), is the most widely distributed, occurring from southern Canada southward to the central Great Plains and the Appalachian Mountains into Georgia and Alabama and along the East Coast as far south as southeastern North Carolina. It has been more than 65 years since geographic variation within this species has been studied. Accordingly, the objectives of this study were to examine geographic variation in Blarina brevicauda and to revise its intraspecific taxonomy as needed.\nA total of 12,390 Holocene specimens of Blarina brevicauda from throughout the geographic range of the species and the fossil material of Blarina fossilis, B. ozarkensis, and B. simplicidens were examined during the course of this study. Nine cranial and mandibular measurements were taken from 2,736 Holocene specimens, which were grouped into 114 operational taxonomic units (OTUs) for statistical analysis. We used a single classification ANOVA to test for significant differences among means of OTUs and a principal component analysis (PCA) to extract eigenvectors and generate a 2-dimensional plot of OTUs.\nOur analysis demonstrates that B. brevicauda consists of 7 well-defined subspecies. Two subspecies, the large-bodied B. b. brevicauda and the medium-sized B. b. talpoides, occupy almost the entire geographic range of the species, with restricted gene flow between these 2 subspecies where their geographic ranges abut in the vicinity of the Mississippi River and its valley. The other 5 subspecies occupy small to modest geographic ranges at the periphery of the range of the species and in isolated geographic areas—an undescribed subspecies on the Cumberland Plateau in Tennessee and adjacent Kentucky, B. b. knoxjonesi along the southeastern coast of North Carolina, another undescribed subspecies on the southern two-thirds of the Delmarva Peninsula, B. b. aloga on Martha’s Vineyard and Nantucket Island, and a third undescribed subspecies in the Kaw River Valley in northeastern Kansas. In each of these geographic areas, gene flow has been stopped or greatly restricted. We have chosen to recognize these 7 subspecies because we believe that each has begun to follow its own evolutionary path. These taxa are arranged in a geographic configuration that fits the pattern termed centrifugal speciation, or the development of small isolated peripheral and sometimes relictual populations as the parent taxon undergoes normal population expansion and contraction cycles. The fact that at least 3 of these peripheral populations are now partially in contact with the parental populations and have not been swamped out genetically indicates to us that they are adapting to their local conditions and are able to maintain their genetic identities. Our morphological data and mitochondrial DNA analyses by other workers indicate that these peripheral subspecies, with the possible exception of the 1 along the Kaw River valley, are derived from B. b. talpoides. These data also indicate that B. b. brevicauda and B. b. talpoides are semi-species.\n[87 pages]
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».