EVOLUTIONARY AND BIOGEOGRAPHIC PATTERNS IN THE ASTEROPYGINAE (TRILOBITA, DEVONIAN) DELO, 1935

This paper presents a phylogenetic analysis of the Asteropyginae Delo, 1935. Sixty-six characters and 39 taxa were employed in a cladistic a nalysis that produced a single most parsimonious tree that is presente d as a hypothesis of asteropyginid relationships. In addition to the p hylogeny generated, 11 new genera are diagnosed: Philipsmithiana, Colt raneia, Stummiana, Bellacartwrightia, Deloops, Tolkienia, Braunops, Am torigreenops, Kennacryphaeus, Modellops, and Hallandclarkeops, and 12 new species are described: Philipsmithiana hyfinkeli, P. burtandmimiae , Armorigreenops leoi, Pelitlina smeenki, Bellacartwrightia jennyae, B . whiteleyi, B. phyllocaudata, B. calderonae, Greenops widderensis, G. barberi, G. grabaui, and Kennacryphaeus harrisae. Traditionally, aste ropyginine taxa in the Appalachian and Michigan Basins of Eastern Nort h America had been assigned to Greenops Delo, 1935, or Greenops (Neome tacanthus) Richter and Richter, 1948. A core of five Eastern North Ame rican species-Greenops boothi (Green, 1837), G. widderensis, new speci es, G. chilmanae Stumm, 1965, G. grabaui, new species, and G. barberi, new species-can still be assigned to Greenops. All other asteropygini ne taxa in Eastern North America must be assigned to different genera. Species referable to Neometacanrhus Richter and Richter, 1948, may be known from the Illinois Basin of Eastern North America, and a species referable to Tolkienia, new genus, may be known from the Michigan Bas in of Eastern North America. The single most parsimonious cladogram wa s also used to investigate biogeographic patterns. In particular, the number of times that independent lineages of asteropyginines invaded f rom what are now Europe and North Africa (called Armorica herein) into Eastern North America during the Devonian was ascertained. Phylogenet ic analysis suggested that there must have been at least four such inv asions, with clades that had primitive European or North African affin ities giving rise to Eastern North American taxa, although no species are shared between Armorica and Eastern North America. One of the line ages that invaded Eastern North America subsequently reinvaded Armoric a. The timing of these invasions and their relation to overall pattern s of faunal evolution in the Middle Devonian of Eastern North America are also discussed. These patterns suggest that the different taxa tha t make up a fauna often arrive during different time intervals, not al l at once.