摘要:

Qualitative aspects of the bacular morphology and variation are surveyed in the seven subspecies currently recognized for Proechimys iheringi (Rodentia: Echimyidae). Each form has a distinct bacular morphology, although the degree of distinctiveness varies among the subspecies. Bacula in P. i. denigratus, P. i. panema, P. i. gratiosus, P. i. bonafidei, and P. i. eliasi share a similarity in overall shape although they differ noticeably from bacula in P. i. paratus and P. i. iheringi. The bacular data seem to support hypotheses derived from cranial morphology and statistical analyses of craniometric traits suggesting that P. iheringi might be a complex of three morphologically similar species.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.129.13339

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The reproductive cycle of the white eared opossum Didelphis albiventris Lund was studied in an area of temperate climate conditions in the region of Buenos Aires Province, Argentina. In 1987–1988 and 1988–1989 the reproductive season began in late August and continued until mid-March. Two distinct breeding periods per season were evident, the first in early September and a second in December. Litter size ranged from 4 to 9. The sex ratio in the pouch was 1:1. Only those females that gave birth early in the season could produce a second litter in December. Progressive pouch mortality was not found. Young opossums were weaned at 3.5 months of age and remained sexually inactive until the next reproductive season. Ages of captured opossums suggest that few animals survive for more than 20 months. Therefore, in the study area, most specimens breed only during one reproductive season. In South America, a latitudinal cline in the timing of the breeding season extends from tropical to temperate areas.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.133.13338

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The highly eusocial bee community of the neotropical Atlantic Rainforest was studied at Boracéia Biological Station in the state of São Paulo, Brazil. In this reserve, 17 species of stingless bees and the introduced Africanized honey bee were found, the latter being the most abundant flower visitor. Of all flowering plants, Asteraceae and Myrtaceae were particularly important as resources for bees. Trophic niche overlap between the various species of stingless bees is evident, and it was generally larger within the tribes Meliponini and Trigonini than between members of different tribes. Nevertheless, in the stingless bee community the competitive pressure is rather uniformly spread. The trophic niche of the Africanized honey bee can be positioned between those of Meliponini and Trigonini. Today this introduced species represents the main competitor in this bee community. However, its impact on native stingless bee populations is apparently buffered by mass-flowering trees which are the most important food plants of the indigenous highly eusocial bees.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.137.13336

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Twenty two species of Trichoptera were collected at 21 sampling stations in the Suquía river basin. Known ranges of 12 were enlarged by more than 300 km and constitute new records for a semiarid region. The different environmental conditions where their larvae live are listed.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.152.13343

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Americabaetis (Insecta: Ephemeroptera: Baetidae), previously considered synonymous with Acerpenna, is reinstated and given generic rank. The genus differs from Acerpenna in lacking hindwings, gills on abdominal segment 1, and a conical process between the male genital forceps, and in possessing apically rounded gills on abdominal segment 7. The genus has a general Neotropical distribution with a northern limit in east-central Mexico. Five new species of Americabaetis are described from South America: A. alphus, new species, from Argentina, Bolivia, Brazil, Chile, and Paraguay; A. labiosus, new species, from Brazil, Paraguay, and Uruguay; A. longetron, new species, from Brazil, Paraguay, and Uruguay; A. maxifolium, new species, from Paraguay; and A. titthion, new species, from Brazil. Americabaetis boriquensis, new combination; A. intermedius, new combination; A. naranjoi, new combination; A. pleturus, new combination; and A. robacki, new combination, are reviewed.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.156.13341

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Ballophilus ramirezi n. sp. (Chilopoda: Geophilomorpha: Ballophilidae) is described from the Iguazú National Park, Province of Misiones. This is the first ballophilid centipede recorded from Argentina.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.170.13335

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In planktonic samples of lotic and lentic environments of the high Paraná River floodplain (States of Paraná and Mato Grosso do Sul) 25 taxa of Difflugidae (Rhizopodea-Sarcodina) were identified, of which Difflugia corona f. tuberculata, D. lobostoma f. multilobata, D. (Pseudocucurbitella) pseudogramen, D. stellastoma, D. kempnyi, D. pleustonica, D. correntina, D. lithophila, D. acuminata var. magna, D. echinulata, Cucurbitella mespiliformis var. africana, C. dentata f. quinquelobata and C. madagascarensis are new records for Brazil.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.179.13342

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Centrolimnesia boopis spec. nov. is described from plankton samples in a shallow lake in the western rain forest of Ecuador. The limnological features of the habitat, and the particular adaptations of the new species for planktonic life are discussed.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.193.13337

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The description of larvae of 7 Neotropical Notiobia s.str. species and a determination key are given. Additionally, information on the larval morphology of two Neotropical species of the subgenus Anisotarsus is presented. It is not possible to distinguish a subgeneric division among the larvae. The larvae of Notiobia species show a wide range of variation, especially in the structure of the mandibles, proportions of head capsule, and development of egg bursters. Mandibular configuration of the Notiobia s.str. species is strongly associated with the particular seed food source. The larvae of N. pseudolimbipennis and N. flavicinctus feed on Ficus (Moraceae). They have an extremely elongated, straight and slender mandible with 4–5 terebral teeth. A similar structure of mandible occurs in the larva of N. nebrioides, which feeds on seeds of Clusiaceae. Species with larvae feeding on seeds of Melastomataceae have a short mandible with less terebral teeth. A short mandible with two terebral teeth like in N. aulica probably represents the plesiomorphic character state. Phylogenetically related species based on both, larval and adult characters, feed on to the same type of seeds.

ISSN:0165-0521    

DOI:10.1076/snfe.31.3.205.13340

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor