title: The emergence of lobsters: phylogenetic relationships, morphological evolution and divergence time comparisons of an ancient group (decapoda: achelata, astacidea, glypheidea, polychelida).
abstract: Lobsters are a ubiquitous and economically important group of decapod crustaceans that include the infraorders Polychelida, Glypheidea, Astacidea and Achelata. They include familiar forms such as the spiny, slipper, clawed lobsters and crayfish and unfamiliar forms such as the deep-sea and "living fossil" species. The high degree of morphological diversity among these infraorders has led to a dynamic classification and conflicting hypotheses of evolutionary relationships. In this study, we estimated phylogenetic relationships among the major groups of all lobster families and 94% of the genera using six genes (mitochondrial and nuclear) and 195 morphological characters across 173 species of lobsters for the most comprehensive sampling to date. Lobsters were recovered as a non-monophyletic assemblage in the combined (molecular + morphology) analysis. All families were monophyletic, with the exception of Cambaridae, and 7 of 79 genera were recovered as poly- or paraphyletic. A rich fossil history coupled with dense taxon coverage allowed us to estimate and compare divergence times and origins of major lineages using two drastically different approaches. Age priors were constructed and/or included based on fossil age information or fossil discovery, age, and extant species count data. Results from the two approaches were largely congruent across deep to shallow taxonomic divergences across major lineages. The origin of the first lobster-like decapod (Polychelida) was estimated in the Devonian (∼409-372 Ma) with all infraorders present in the Carboniferous (∼353-318 Ma). Fossil calibration subsampling studies examined the influence of sampling density (number of fossils) and placement (deep, middle, and shallow) on divergence time estimates. Results from our study suggest including at least 1 fossil per 10 operational taxonomic units (OTUs) in divergence dating analyses. [Dating; decapods; divergence; lobsters; molecular; morphology; phylogenetics.].
authors.affiliation: Department of Biology, Florida International University, 3000 NE 151st Street, North Miami, FL 33181, USA; hbracken@fiu.edu.
authors.forename: Heather D
authors.initials: HD
authors.lastname: Bracken-Grissom
authors.affiliation: Australian Museum, 6 College Street, Sydney, NSW 2010, Australia;University of New South Wales, Kensington, NSW 2052, Australia;
authors.forename: Shane T
authors.initials: ST
authors.lastname: Ahyong
authors.affiliation: School of Mathematical Sciences, University of Nottingham, Nottingham, UK;
authors.forename: Richard D
authors.initials: RD
authors.lastname: Wilkinson
authors.affiliation: Department of Geology, Kent State University, Kent, OH 44242, USA;
authors.forename: Rodney M
authors.initials: RM
authors.lastname: Feldmann
authors.affiliation: Kent State University at Stark, 6000 Frank Avenue NW, North Canton, OH 44720, USA;
authors.forename: Carrie E
authors.initials: CE
authors.lastname: Schweitzer
authors.affiliation: Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA;
authors.forename: Jesse W
authors.initials: JW
authors.lastname: Breinholt
authors.affiliation: Brigham Young University, 401 WIDB, Provo, UT 84606, USA;
authors.forename: Matthew
authors.initials: M
authors.lastname: Bendall
authors.affiliation: Unitat Mixta Genòmica i Salut CSISP-UV, Institut Cavanilles Universitat de Valencia, C/Catedrático Jose Beltran 2,46980 Paterna, Spain;
authors.forename: Ferran
authors.initials: F
authors.lastname: Palero
authors.affiliation: Institute of Marine Biology and Center of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, Keelung 20224, Taiwan, R.O.C.;
authors.forename: Tin-Yam
authors.initials: TY
authors.lastname: Chan
authors.affiliation: Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504, USA;
authors.forename: Darryl L
authors.initials: DL
authors.lastname: Felder
authors.affiliation: Laboratory of Bioecology and Crustacean Systematics, Department of Biology, FFCLRP, University of São Paulo (USP), Ave. Bandeirantes 3900, CEP 14040 - 901, Ribeirão Preto, SP Brazil;
authors.forename: Rafael
authors.initials: R
authors.lastname: Robles
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong;
authors.forename: Ka-Hou
authors.initials: KH
authors.lastname: Chu
authors.affiliation: Institute of Marine Biology and Center of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, Keelung 20224, Taiwan, R.O.C.;School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong;
authors.forename: Ling-Ming
authors.initials: LM
authors.lastname: Tsang
authors.affiliation: Brigham Young University, 401 WIDB, Provo, UT 84606, USA;
authors.forename: Dohyup
authors.initials: D
authors.lastname: Kim
authors.affiliation: Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA;
authors.forename: Joel W
authors.initials: JW
authors.lastname: Martin
authors.affiliation: George Washington University, Computational Biology Institute, Ashburn, VA 20147, USA;
authors.forename: Keith A
authors.initials: KA
authors.lastname: Crandall
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics; D005075:Biological Evolution; D033364:Decapoda / Q000033:anatomy & histology* / Q000145:classification* / Q000235:genetics; D005580:Fossils; D010802:Phylogeny; D013995:Time
chemical_list: D060829:Arthropod Proteins