DOI: 10.5061/dryad.gmsbcc2xm
title: New mid-Cretaceous macrothelids showing a similar living mode to extant Macrothelidae (Araneae: Mygalomorphae)

description: Five new spider species of the family Macrothelidae (Araneae:
 Mygalomorphae) are described from mid-Cretaceous Kachin amber, Myanmar. A
 new genus Acanthomacrothele gen. nov. is established for three new
 species: A. pauciverrucae sp. nov., A. geminata sp. nov. and A.
 longicaudata sp. nov. Both male and female specimens of A. pauciverrucae
 sp. nov. are described, representing a rare case of a fossil spider with
 both sexes known. We also describe an unidentified juvenile of
 Macrothelidae to document different developmental stages of Cretaceous
 species. To test the phylogenetic position of the new fossils, we
 performed phylogenetic analyses using both topology-unconstrained and
 topology-constrained methods. Our analyses supported the placement of
 Acanthomacrothele gen. nov. in Macrothelidae, although its phylogenetic
 relationship to other genera of Macrothelidae differed among different
 analytical methods. The fossils documented here have elongated, widely
 spaced posterior lateral spinnerets, compact rectangular group of eyes on
 a tubercle and more spines on male tibia of anterior legs than female,
 similar to extant macrothelids, suggesting that they probably have similar
 retreat construction behavior, habitat preference and mating position to
 their living relatives.
description: # New mid-Cretaceous macrothelids showing a similar living mode to extant
 Macrothelidae (Araneae: Mygalomorphae) ## Description of dataset This
 dataset comprises the raw data files and scripts supporting the article
 "New mid-Cretaceous macrothelids showing a similar living mode to
 extant Macrothelidae (Araneae: Mygalomorphae)". In this study, to
 test the phylogenetic position of the genera Acanthomacrothele and
 Promacrothele, we performed phylogenetic analyses using both
 topology-unconstrained and topology-constrained methods. Unconstrained
 phylogenetic analyses were carried out using maximum parsimony (MP),
 Bayesian inference (BI) and maximum-likelihood (ML) methods. Constrained
 phylogenetic analyses were carried out using MP and BI methods following
 Fikáček et al. (2020). Alternative placements of Promacrothele and
 Acanthomacrothele, and their posterior probabilities were calculated and
 visualized using the “showing_position_of_fossil_taxon.R” script using the
 complete set of posterior probability trees and the consensus tree as
 input data. ## List of files: Constrained_Matrix.nex (for constrained BI
 analyses in MrBays) Constrained_Matrix.ss (for constrained MP analyses in
 TNT) Constrained_Matrix_Acanthomacrothele.nex (for the analyses of
 alternative placements of Acanthomacrothele using BI method in MrBays)
 Constrained_Matrix_Promacrothele.nex (for the analyses of alternative
 placements of Promacrothele using BI method in MrBays)
 Reference_tree_WINCLADA.tre (reference tree used as a set of constraints
 built in WinClada) Reference_tree_WINCLADA_numbered_taxa.tre (reference
 tree with numbered taxa used as a set of constraints built in WinClada)
 showing_position_of_Acanthomacrothele.R (R script used in the analyses of
 alternative placements of Acanthomacrothele)
 showing_position_of_Promacrothele.R (R script used in the analyses of
 alternative placements of Promacrothele) Unconstrained_Matrix.nex (for
 unconstrained BI analyses in MrBays) Unconstrained_Matrix.phy (for
 unconstrained ML analyses in IQ-TREE) Unconstrained_Matrix.ss (for
 unconstrained MP analyses in TNT)