Cladistics and distribution of Euxanthe butterflies (Nymphalidae: Charaxinae)

A cladistic analysis of the 6 species of Euxanthe is given utilizing 15 characters, and the species' geographical distributions discussed in relation to the proposed cladogram. The division of the genus into two subgenera by past revisers is seen to be justified. The relatively rapid anagenesis of E. madagascariensis is considered, and mimicry in the group discussed. A key to the 15 species and subspecies taxa is given, and each is revised. Notes on the biology of the species and subspecies are included, 7 lectotypes are designated and 2 new synonyms established.     

Biogeographic analysis of the ant genus Gnamptogenys Roger in South-East Asia-Australasia (Hymenoptera: Formicidae: Ponerinae)

The distribution range of ants of the genus Gnamptogenys is analysed, with special reference to the Old World species, and two closely related genera: Rhytidoponera and Ectatomma. The study is based upon a cladistic biogeographic analysis, recognizing the following areas of endemism: Central America, South America, Philippine Islands, New Guinea, Australia, Solomons/Fiji and South-East Asia. These results are followed by a consensus of different information sources (phylogenetic, natural history, past and present distribution, palaeogeographical and palaeoclimatological) for explaining the present and past distribution of Gnamptogenys and related genera. The area cladogram shows repeated instances of sister relations between Old World and New World taxa at different depths within the tree. Subtree analysis further suggests a common sister relation between Gondwanan landmasses. The distribution of the Gnamptogenys is interpreted as a product of vicariance, starting with the separation of Gondwana, and subsequent dispersal into South-East Asia and Melanesia via rafting on the Australian craton. The desiccation of Australia during the Oligocene was detrimental to the presence of Gnamptogenys but favoured expansion of Rhytidoponera. The study illustrates that a cladistic biogeographic scenario may be supported by a consensus of data from various sources, and also suggests a pre-Tertiary diversification of ant fauna.     

New record and southern range extension for the Mearn's grasshopper mouse ( Onychomys arenicola Mearns, 1896) in Veracruz, Mexico

Mearn’s grasshopper mouse ( Onychomys arenicola ) in Mexico is found primarily in the central and northern states. This is the first report of the genus Onychomys in the state of Veracruz, based on 7 captured specimens (3 collected). This finding extends the species’ known distribution by approximately 470 km east-southeast. In addition, this record increases the alpha diversity of terrestrial mammals for the state of Veracruz to 192 species.     

Geographic patterns of ground-dwelling arthropods across an ecoregional transition in the North American Southwest

We examined the biogeographic patterns of ground-dwelling arthropod communities across a heterogeneous semiarid region of the Southern Rio Grande Rift Valley of New Mexico. Our 3 sites included portions of 5 ecoregions, with the middle site a transition area where all ecoregions converged. We addressed the following 3 questions: (1) Do the species assemblage patterns for ground arthropods across habitats and sites conform to recognized ecoregions? (2) Are arthropod assemblages in distinct vegetation-defined habitats within an ecoregion more similar to each other or to assemblages in similar vegetation-defined habitats in other ecoregions? (3) Is there a detectable edge effect with increased arthropod diversity in the area of converging ecoregions? We encountered 442 target arthropod species from pitfall traps operating continuously for 7 years over a series of different habitats at each of the 3 sites. We examined geographic distributions of spider and cricket/grasshopper species in detail, and they showed affinities for different ecoregions, respectively. Each habitat within a study site supported a unique overall arthropod assemblage; nevertheless, different habitats at the same site were more similar to each other than they were to similar habitats at other sites. Overall arthropod species richness was greatest in the area where all 5 ecoregions converged. Arthropod species and their geographic distributions are poorly known relative to vascular plants and vertebrate animals. Findings from this research indicate that ecoregional classification is a useful tool for understanding biogeographic patterns among arthropods.     

Insular biogeography of mammals in the Great Salt Lake

The distribution of 21 species of nonvolant mammals among nine islands in the Great Salt Lake was analyzed for biogeographic patterns. The number of species inhabiting an island is closely correlated with island area That the slope of the regression line describing this relationship (z or b) is relatively shallow compared to (1) totally isolated island systems or (2) island systems where an equilibrium between rates of colonization and extinction have been attained suggests that isolation plays little role in accounting for the variation in mammalian species diversity among islands. Stepwise multiple regression confirms this, while demonstrating that area alone accounts for 88 percent of the variation in species diversity among islands. However, endemic subspecies comprise a significant proportion of the insular mammalian fauna, suggesting that isolation for small mammals restricted to certain habitats may be substantial. A general scenario of the processes determining insular mammalian diversity and endemism is discussed for the Great Salt Lake, where the dynamic lake level creates a potential for different biogeographic processes over time.     

Novel records and observations of the barnacle Stephanolepas muricata (Cirripedia: Balanomorpha: Coronuloidea); including a case for chemical mediation in turtle and whale barnacles

We report new distribution and host records of the turtle barnacle Stephanolepas muricata Fischer. Ours is the first study to document this species' occurrence in Mexico and in the Atlantic Ocean (North Carolina, Georgia and Florida: USA). We also present the first record of S. muricata from olive ridley sea turtles, Lepidochelys olivacea (Eschscholtz). We discuss the physical and ecological characteristics associated with the specimens collected and present evidence suggesting the likelihood of chemical mediation between embedding coronuloid barnacles like S. muricata and host turtles. We provide the first data on the diet and fecundity of S. muricata.     

The effect of altitude on arid inselbergs along a bioclimatic gradient

Twenty-four inselbergs in four distinct landscapes along a biogeographic gradient from mesic winter rainfall in the southern Namib to arid summer rainfall in the northern Namib were analysed. Declining similarity of vegetation between matrix (surrounding plains) and inselbergs with altitude were exhibited in most inselbergs, irrespective of biogeographic region, rock types and height above surroundings. Some inselbergs showed the least congruence with matrix vegetation on upper slopes, others with the top of inselbergs. This is probably related to the nature of the individual inselbergs, e.g. with steep cliffs in the upper reaches supporting plant species adapted to more mesic conditions. Most trends of declining similarity between matrix and inselberg habitats were maintained across the investigated bioclimatic regions. Even low inselbergs clearly supported vegetation very distinct from the surrounding area. Their contribution to species richness of a landscape is therefore unquestionable and adequate protection of such landscapes is needed where human impacts are severe.     

Can we agree on an ecological classification of subterranean animals?

That the ties between any obligate subterranean species and the hypogean environment depend on the interplay of a species' own physiological characteristics and all of the ecological characteristics of the adjacent epigean habitat(s), including biotic factors, has been emphasized. The reasons why troglomorphy cannot be included within criteria for classifying cave dwellers have been demonstrated. After a review of historic classifications, standardized definitions of the most widely used terms are proposed. The most easily recognized are four categories which are terminological approximations of the classic Schiner‐Racovitza terminology: (1) troglobiont is a species or population, strictly bound to a hypogean habitat; (2) eutroglophile is an essentially epigean species, but able to maintain a permanent subterranean population; (3) subtroglophile is inclined perpetually or temporarily to inhabit a subterranean habitat but is bound to the surface for some biological functions (e.g. feeding); (4) trogloxene is a species only occurring sporadically underground.     

Fossil history of Notiosorex (Soricomorpha: Soricidae) shrews with descriptions of new fossil species

Notiosorex shrews (Soricomorpha: Soricidae) have a fossil history that extends to the Miocene (i.e., mid-Hemphillian). In the intervening 6.69 million years, N. repenningi, N. jacksoni, and what heretofore was considered N. crawfordi existed with varying degrees of overlap in occurrence timewise and in geographic distribution in areas of the southwestern United States and northern Mexico. Examination of unusually small fossil specimens of Notiosorex indicated the presence of another species referable to this genus present in late Pleistocene- (i.e., early Wisconsinan) to Holocene-aged deposits. Based on statistical analyses, these specimens were as distinct from any of the other fossil or extant species of Notiosorex as any other pair of species within the genus. I referred these specimens to the new species N. harrisi. Analyses also indicted fossils heretofore considered N. crawfordi were equally distinct from other forms of Notiosorex. I referred them to the new species N. dalquesti. Individuals referred to the fossil species of Notiosorex range in size from the smaller N. harrisi, to N. dalquesti, to N. jacksoni, to the larger N. repenningi. This size differential could be related to changing climatic conditions with the concomitant ecological succession that occurred, which provided a driving force for speciation within the genus. The changing climate and unique morphological and physiological adaptations allowed fossil taxa of Notiosorex to expand their distributions into areas subsequently less suitable for other forms of shrews. Present-day notiosoricini shrews occur throughout much of the southwestern United States and northern Mexico in a variety of habitats in association with rough, rocky terrain. Thus, if climate, even indirectly, was the driving force for speciation among fossil taxa of Notiosorex, other forces must have acted on the extant species N. cockrumi, N. crawfordi, N. evotis, and N. villai.     

Floristic analysis of the southwestern United States

A study was made of the distributions of native, terrestrial, vascular plants occurring in 50 local floras from throughout the Basin and Range and Colorado Plateau physiographic provinces of the southwestern United States. The objectives of the study were to objectively define and describe the floristic elements-assemblages of species with roughly coincident geographic distribution-occurring in the southwestern United States and to determine what such assemblages reveal about the floristic history of the region. The total flora (native, terrestrial species only) of the Southwest is estimated at 5,458 species, 77% of which were recorded in 1 or more of the local floras. Nearly 22% of these species are endemic to the study region. A majority of the species were found to be relatively rare. The average range of a species included only 4 floras, and 90% of the species were recorded from 11 or fewer floras; only 81 species (1.5%) were recorded from 50% or more of the floras. Trees constitute 2% of the regional flora and have the widest average distribution; perennial herbs constitute 59% of the flora and have the most restricted distributions.  Factor analysis was used to identify seven floristic elements for the region: a Great Basin element, a Mojavean element, a Colorado Plateau element, a Chihuahuan element, an Apachian element, and a Mogollon element. This factor analysis solution was shown to satisfy criteria of interpretability and consistency. The Mojavean, Colorado Plateau, and Apachian elements are believed to be autochthonous. The other four elements show high overlap in species composition with one or more adjacent regions. Each floristic element is mapped to show its geographic form and distribution. Analysis of these maps shows how the existence of objectively defined floristic elements is not contradictory to either the individualistic view of the distribution of a species or local continuity of vegetation and flora. The rarity of the majority of species and the clear association of floristic elements with rather narrowly circumscribed Holocene environments suggests that many Southwestern species have migrated little and are of rather recent, probably postglacial origin. Geographic “principles” derived from the distribution patterns of relatively few, widespread, dominant, usually woody species may not be applicable to entire, regional floras.       

American pikas inhabit low-elevation sites outside the species’ previously described bioclimatic envelope

It has been suggested that Nearctic pikas ( Ochotona spp.) are good biogeographic indicators of regions containing rocky, mesic, and cool habitat characterized by long winters and short summers. I examined whether populations of pikas inhabiting distinct low-elevation locales (121–255 m) are faithfully restricted to long-winter and shortsummer conditions by monitoring the climate associated with American pikas ( Ochotona princeps ) in the southern part of the Columbia River Gorge, Oregon. Ambient air temperatures and weather conditions in the vicinity of 4 pika-occupied rockslides were monitored with remote temperature loggers and weather stations from June 2000 to June 2001. Temperatures were compared to long-term averages recorded within the area. I detected pikas inhabiting locales where some temperatures lie outside of the limiting climatic values previously calculated for regions containing pikas. Mild winter temperatures at these pika locations show that long-winter temperatures and snow accumulation associated with typical habitat may not be requirements for pikas in some low-elevation habitat. When using climatic conditions experienced by extant pikas to estimate local paleoenvironments surrounding fossil sites and to anticipate effects of climate change on future pika distributions, I determined that pika sites in the Columbia River Gorge indicate that the association of pikas with long-winter habitat should be considered uncertain. These results highlight the need for further investigation into how local temperatures affect the distribution, behavior, and persistence of low-elevation pikas.     

Mourning dove numbers on different seral communities in the Chihuahuan Desert

Mourning Doves are the most commonly hunted game bird in New Mexico based on hunter harvest data collected by New Mexico Department of Game and Fish. Research is limited on the influence of rangeland ecological condition on Mourning Dove ( Zenaida macroura ) populations in the Chihuahuan Desert of New Mexico. Mourning Dove numbers were evaluated periodically (1988-1989) on ranges in late- and mid-seral conditions in south central New Mexico based on the Dyksterhuis quantitative climax procedure. Strip transect procedures were used to estimate Mourning Dove populations. Concurrently, vegetation canopy cover was determined by line intercept. On the basis of percent cover, grasses were the most abundant group on late-seral range while shrubs dominated mid-seral range. Mourning Dove sightings did not differ ( P > 0.05) between late- and mid-seral ranges, nor did they differ ( P > 0.05) among grassland, shrubland, and shrub-grass mosaic communities. Mourning Dove populations showed seasonal differences ( P < 0.05), with numbers highest in summer and fall and lowest in winter and spring. Data from our study indicate that Chihuahuan Desert ranges in either mid- or late-seral stages provide equally suitable habitat for Mourning Doves.     

Effects of habitat disturbance on diets of Great Horned Owl ( Bubo virginianus ) in a cold desert

To determine the potential effect of habitat disturbance, Great Horned Owl ( Bubo virginianus ) diets were quantified in disturbed and undisturbed habitats over a 2-year period at Dugway Proving Ground in the Great Basin Desert of Tooele County, Utah. Invertebrates were the most abundant prey by count, whereas mammals constituted the majority of diet by biomass. Species richness in the diet did not differ between habitats or among seasons after correcting for the number of pellets in each sample. However, the number of vertebrate species was greater than the number of invertebrate species in the diet, and this ratio differed between disturbed and undisturbed habitats. Invertebrate species made up a greater proportion of total species richness in the diet in the undisturbed than the disturbed habitat. Nineteen species occurred in the diet in only 1 of the 2 habitat types (7 unique species in disturbed habitat, 12 unique species in undisturbed), but all such species were rare and contributed little both by count and biomass to the overall diet. Of the 20 most important species found in owl diets in both habitats (based on percent biomass), none were more common in 1 habitat than the other after correcting for multiple tests. Although there were minor differences in the diet between disturbed and undisturbed habitats, habitat alteration and degradation of native vegetation on Dugway Proving Ground did not affect the major components of the diet of Great Horned Owls.     

Elevational zonation of birds,insectivores, rodents and primates on the slopes of the Andringitra Massif,Madagascar

A review is presented of the birds, lipotyphlans, rodents and lemurs occurring across an elevational transect from 720 to 2450 m within the 31160ha Parc National (PN) d'Andringitra in south-central Madagascar. The broad range of habitats within this reserve consists of lowland forest, montane forest, sclerophyllous forest, montane thicket, to open areas of bare rocks covered by geophytes. Eight different zones were surveyed across this elevational range for most of these four vertebrate orders. On the basis of these surveys and other sources of information, 106 species of birds, 16 species of Lipotyphla, 11 species of rodents (including two introduced species) and 13 species of primates are documented within the reserve. Surveys of the carnivores are incomplete, although eight species, three of which are introduced, have been recorded in the reserve. Forty-eight species of non-volant mammals are known from the Andringitra Massif, 43 of which are endemic to Madagascar. The highest species richness for birds was 85 species in the disturbed lowland forest at 720m zone and there was a subsequent reduction in the number of species at each site with increasing elevation. The two zones at 1210 and 1625 m with montane and mixed montane/sclerophyllous forest had the greatest species richness of non-volant mammals with 26 species (25 non-introduced). Lemurs showed decreasing species richness with increasing elevation. Small mammals showed broad elevational ranges and high species diversity in the middle to upper portion of the forest zone, with lipotyphlans peaking at 1990 m and rodents between 1625 and 1960 m. About 88 species of extant native rodents, carnivores, lipotyphlans and primates are currently recognized to occur on Madagascar. Thus, the PN d'Andringitra holds nearly 50% of the total known fauna of these groups from the island. This relatively small reserve plays a major role in safe-guarding a large proportion of the non-volant mammal fauna of Madagascar.     

Larval development of Maja crispata Risso 1827 (Crustacea,Decapoda, Majidae) reared in the laboratory

The morphology of the zoea and megalop of Maja crispata are described from laboratory-reared material, and compared with other two spider crabs belonging to the subfamily Majinae, Maja squinado and Maja goltziana, recorded in the same region of the eastern Atlantic. The diagnostic characters allowing the separation of these species' larvae are tabulated and discussed.     

Soil depth effects on Chihuahuan Desert vegetation

We evaluated relationships between soil depth and vegetation standing crop components over a 3-year period on 3 adjoining pastures with similar size, vegetation, and soils on the Chihuahuan Desert Rangeland Research Center in south central New Mexico. Soils on our study pastures are primarily light sandy loams varying from a few centimeters to 1 m or more in depth underlain by a calcium carbonate layer. Study pastures were ungrazed in 1995 and 1996 and conservatively grazed in 1997. Linear regression equations using perennial grass standing crop (kg ha -1 ) and honey mesquite ( Prosopis glandulosa Torr.) cover (%) as dependent variables and soil depth as the independent variable were significant ( P P = 0.78, n = 18), but a significant ( P = 0.01) negative correlation occurred on deep soils ( r = -0.67, n = 15). Perennial grass standing crop differed greatly among years when data were pooled across pastures, ranging from 64 kg ha -1 in 1995 to 248 kg ha -1 in 1997. Our study shows that soil depth has a major influence on Chihuahuan Desert vegetation. Perennial grasses are favored by shallow sandy soils while deep sandy soils favor honey mesquite.