1. The Madro-Tertiary Geoflora comprises semiarid live oak-conifer woodland, chaparral, arid subtropic scrub, plains (desert) grassland, and subdesert to desert vegetation. 2. The taxonomic and adaptive relations of its plants suggest that it was derived chiefly from subtropical to warm temperate groups that evolved in response to the expansion of a new adaptive zone—dry climate. 3. The geoflora seems to have had an origin in southwestern North America because (a) types that appear to be ancestral to Madro-Tertiary lineages are represented in the Cretaceous and Paleocene floras of that region, (b) they are not known from the temperate Arcto-Tertiary Geoflora to northward, and (c) they are not recorded in the humid phases of the Neotropical-Tertiary Geoflora. 4. Geologic and paleoclimatic data suggest that southwestern North America was generally a lowland region, characterized by tropic savanna climate during the Cretaceous and Early Tertiary. 5. During this interval, ancestral Madro-Tertiary phylads probably were evolving chiefly in sites away from the moist lowland floodplains, in drier areas provided by local edaphic and climatic conditions. 6. With a strong linear component to selection imposed by a gradual trend toward increased aridity, these scattered, isolated phylads of subtropic to warm temperate affinities may have been undergoing megaevolution during the Cretaceous and Paleocene, giving rise to numerous, highly specialized taxonomic and adaptive types. 7. When first recorded in moderate numbers in the Eocene and early Oligocene, they are closely similar to modern species. 8. As dry climates continued to expand in area and to increase in severity, the Madro-Tertiary Geoflora migrated widely over southwestern North America. The stage during which it attained dominance in each province was governed chiefly by geographic position and time. 9. In response to the evolution of new dry climates in the later Cenozoic, each of the generalized Madro-Tertiary communities was differentiated into a number of modern associations that are adapted now to more localized dry environments.

Evolution of the Madro-Tertiary geoflora

Evolutionary history of the genus Rhamdia (Teleostei: Pimelodidae) in Central America

http://www.zo.utexas.edu/faculty/antisense/papers/HillisandWilcox2005.pdf

Phylogeny of the New World true frogs (Rana).

A phylogenetic hypothesis of the fungus-growing ants (subfamily Myrmicinae, tribe Attini) is proposed, based on a cladistic analysis utilizing forty-four morphological characters (109 states) of the prepupal worker larva. The fifty-one attine species analysed include representatives of eleven of the twelve currently recognized attine genera, excluding only the monotypic workerless parasite Pseudoatta; the non-attines include two outgroups (species of the basal myrmicine genera Myrmica and Pogonomyrmex), two myrmicine species presumed to be distantly related to the attines, and twelve species representing taxa that have been proposed by prior workers as possible sister groups of the Attini. There is strong character support for the monophyly of the Attini and for a sister-group relationship of the Attini and the Neotropical Blepharidatta brasiliensis. The Attini are divided into two distinct lineages, an ‘apterostigmoid’ clade (containing Apterostigma and Mycocepurus) and an ‘attoid’ clade (containing all other attine genera except Myrmicocrypta). The attine genus Myrmicocrypta appears to be paraphyletic with respect to these two groups; the species M.buenzlii in particular retains many attine plesiomorphies.



These results indicate that the fungus-growing behaviour had a single evolutionary origin in the ants. They also indicate that mycelium cultivation is plesiomorphic and that yeast cultivation is derived within the Attini, overturning the long-standing assumption that the yeast-growing Cyphomyrmex species are the most primitive Attini. Behavioural and ecological investigations into the origin and evolution of the fungus-growing behaviour might more profitably focus on species in the attine genus Myrmicocrypta, as well as those in the closely related non-attine genera Blepharidatta and Wasmannia.

A phylogenetic analysis of the fungus‐growing ants (Hymenoptera: Formicidae: Attini) based on morphological characters of the larvae

More than 775 nomenclatural changes are proposed and nomenclatural problems are discussed for the Staphylinidae. Two generic names are proposed as replacement names: Torobus for species formerly in Trigonopselaphus, and Ryvkinius for the preoccupied Mesoporus Ryvkin. Type species are fixed or problems with the type species are discussed for: Entomoculia, Eumegalopsidia (an unavailable name), Anthobium, Lesteva, Phyllodrepoidea, Aleioglyphesthus, Bolitogyrus, Cephalonthus, Diatrechus, Euremus, Indoquedius, Philothalpus, Philonthopsis, Pseudoremus, Leptophius, Stenus (Nestus), Coproporus, and Paratachinus. The type species for Entomoculia, Anthobium, Phyllodrepoidea, Leptophius, and Stenus (Nestus) are fixed under provisions of article 70.3 of the Code. Emendations are cited or one of multiple original spellings adopted in Bledius, Bryoporus, Carpelimus, Edaphus, Eleusis, Gauropterus, Indosorius, Lispinus, Lithocharodes, Medon, Osorius, Philonthus, Piestus, Pinophilinus, Platydracus, Priochirus, Pr...

M. v. Schlereth

Papers

Biologia Centrali-Americana