The earliest palpimanid spider (Araneae: Palpimanidae), from the Crato Fossil-Lagerstatte (Cretaceous, Brazil).

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Date: May 2021
From: The Journal of Arachnology(Vol. 49, Issue 1)
Publisher: The American Arachnological Society
Document Type: Article
Length: 4,696 words
Lexile Measure: 1080L

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Abstract :

The Crato Formation (Lower Cretaceous) of Brazil is well known for an exceptionally preserved terrestrial arthropod fossil assemblage. Spiders are relatively abundant, but few have been formally described. A fossil spider belonging to the family Palpimanidae. arancophageous ground-dwelling spiders with distinctly robust front legs, is preserved with the dorsal side hidden within the rock matrix. For the first lime, micro-computed tomography (micro-CT) was used to image a fossil spider preserved in a rock matrix, to reveal the dorsal side of this specimen, revealing the eye arrangement, a useful taxonomic character in most spiders, and a deflated abdomen, likely the result of taphonomic processes. The specimen possesses other distinguishing characteristics of Palpimanidae, including an inflated first leg femur, a heavily sclerotized scutum, and a reduced number of spinnerets (2) surrounded by a sclcrotizcd ring. The spider has eight eyes with the lateral pairs extremely close together, a trait suggestive of the subfamily Chcdiminae. The specimen also possesses an unusual first leg patella with a retrolalcral excavation and a thorn-like projection. A new genus is erected, and the spider is named Cretapalpus vittari gen. et sp. nov. A phylogcnclic analysis including extant species from each of the subfamilies within Palpimanidae places the fossil at the base of Chcdiminae + Otiolhopinac. This is the earliest reported fossil palpimanid and first chediminc from South America. A fossil chediminc in South America is not surprising because the South American and African plates were still relatively close during the Early Cretaceous. Keywords: Mesozoic, palcobiogeography. Palpimanoidea. systematica

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Gale Document Number: GALE|A663655395