Australopithecus afarensis (3 7-3 0 Ma) is the earliest known spe

Australopithecus afarensis (3.7-3.0 Ma) is the earliest known species of the australopith grade in which the adult cranial base can be assessed comprehensively. This region of the adult skull was known from fragments in the 1970s, but renewed fieldwork beginning in

the 1990s at the Hadar site, Ethiopia (3.4-3.0 Ma), recovered two nearly complete crania and major portions of a third, each associated with a mandible. These new specimens confirm that in small-brained, bipedal Australopithecus the foramen magnum and occipital condyles were anteriorly sited, as in humans, but without the foramen’s forward inclination. In the large male A.L. 444-2 this is associated with a short basal axis, compound screening assay a bilateral expansion of the base, and an inferiorly rotated, flexed occipital squama-all derived characters shared by later australopiths and humans. However, in A. L. 822-1 (a female) a more primitive morphology is present: although the foramen and condyles reside anteriorly on a short base, the nuchal lines are very high, the nuchal plane is very steep, and the base is as relatively narrow centrally. A.L. 822-1 illuminates fragmentary specimens in the 1970s Hadar

collection that hint at aspects of this primitive suite, BX-795 suggesting that it is a common pattern in the A. afarensis hypodigm. We explore the implications of these specimens for sexual dimorphism and evolutionary scenarios of functional integration in the hominin cranial base.”
“Background: Separating males and females at the early adult stage did not ensure the virginity of females of Anopheles arabiensis

(Dongola laboratory strain), whereas two years earlier this method had been successful. In most mosquito species, newly emerged males and females are not able to mate successfully. For anopheline species, a period of 24 h post-emergence is generally required for the completion of sexual maturation, which in males includes a 180 rotation of the genitalia. In this study, the possibility of an unusually shortened sexual buy RGFP966 maturity period in the laboratory-reared colony was investigated.

Methods: The effect of two different sex-separation methods on the virginity of females was tested: females separated as pupae or less than 16 h post-emergence were mated with males subjected to various doses of radiation. T-tests were performed to compare the two sex-separation methods. The rate of genitalia rotation was compared for laboratory-reared and wild males collected as pupae in Dongola, Sudan, and analysed by Z-tests. Spermatheca dissections were performed on females mated with laboratory-reared males to determine their insemination status.

Results: When the sex-separation was performed when adults were less than 16 h post-emergence, expected sterility was never reached for females mated with radio-sterilized males.

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