Characters of multituberculates neglected in phylogenetic analyses of early mammals

Multituberculate anatomy is compared with that of other mammals, with an emphasis on the characters that have either been neglected or misinterpreted in previous analyses of early mam mal relationships. These are: brain structure, backward masticatory power stroke (along with aspects of cranial design), and foot structure. New data on ear ossicles and a controversy con cerning multituberculate posture are also discussed. The following characters of multitubercu late skull and lower jaw are interpreted to be related to the backward masticatory power stroke: anterior orbital area roofed dorsally and without a floor (characteristic of advanced multituber culates), parietal postorbital process, lack of the angular process and a more anterior position of the coronoid process and masseteric fossa than in all other mammals. It is argued that the parallel development in the cranial structure of multituberculates and other mammals was lim ited by the backward masticatory power stroke of multituberculates that resulted in different configuration of the masticatory musculature and related osteology. In the postcranial skeleton the parallelism was limited by the structure of the multituberculate foot, in which the calca-neum contacts the fifth metatarsal (MtV) and the middle metatarsal (MtIII) is abducted 30° from the longitudinal axis of the tuber calcanei. Backward masticatory power stroke and related skull design do not show unequivocally whether multituberculates originated from some ‘tri-conodonts’ (a polyphyletic group), or independently from all other mammals from cynodonts. The foot structure refutes the origin of multituberculates from the Morganucodontidae. The brain structure allies the multituberculates with the Triconodontidae, the postcranial skeleton of which remains unknown. New data on ear ossicles suggest close relationships of multituber culates to all modern mammals. Lack of uncontested pre-Kimmeridgian multituberculates dis proves the separate origin of multituberculates from cynodonts.     

On the metatherian nature of the Deltatheroida, a sister group of the Marsupialia

A lower molar of Sulestes sp., a deltatheridiid from the Coniacian of Uzbekistan, is described. The Deltatheroididae new fam. is erected. The Deltatheroididae and Deltatheridiidae are assigned to the order Deltatheroida Kielan-Jaworowska 1982 and it is argued that the Deltatheroida are metatherians, a sister group of Marsupialia. The Deltatheroida have at least an incipient alisphenoid bulla, three premolars sharply differentiated morphologically from four molars, a very large stylar area and the protoconid higher than the metaconid. They differ from known Cretaceous marsupials in having a tendency to lose the last molar, in having a small protocone, a narrow and short talonid, and a hypoconulid and entoconid not approximated. Known deltatheroidan taxa are compared. Relationships of the Deltatheroida and Aegialodontia are discussed. The place of metatherian origin is still not known with certainty. □ Mammalia, Metatheria, Deltatheroida, Marsupialia, Cretaceous, Asia, Paleobiogeography.     

Absence of ptilodontoidean multituberculates from Asia and its palaeogeographic implications

Gobibaatar parvus Kielan-Jaworowska 1970, formerly the only representative of the Ptilodontoidea in Asia, is recognized to be a junior synonym of Kryptobaatar dashzevegi Kielan-Jaworowska 1970 and allocated to the Taeniolabidoidea. Members of the Ptilodontoidea are thus currently unknown in Asian faunas. Chulsanbaataridae Kielan-Jaworowska 1974 is a junior synonym of the Eucosmodontidae Jepsen 1940. The absence of Ptilodontoidea in Asia gives further support to the theory of one-way Late Cretaceous dispersal of mammals from Asia to North America. The Marsupialia and Ptilodontoidea originated in the New World and never reached Asia, whereas the Taeniolabidoidea and Eutheria originated in Asia and dispersed to North America during the Late Cretaceous.     

Ornamentation types of conidia and conidiogenous structures in fasciculate Penicillium species using scanning electron microscopy

KOZAKIEWICZ, Z., 1988. Ornamentation types of conidia and conidiogenous structures in fasciculate Penicillium species using scanning electron microscopy. As part of a multidisciplinary approach to the taxonomy of the fasciculate Penicillium species, the conidial ornamentation of 320 strains was examined in order to determine the types and range of ornamentation and assess the stability of this feature as a taxonomic character.
Five conidial ornamentation classes were identified: echinulate, tuberculate, reticulate, microtuberculate and microverrucate. The technique of cryoscanning was used for examining the penicillus, and assessing such characters as roughening, shape and orientation of the branches. The method provides a fast means of examining freshly frozen material in the absence of artefacts associated with air-drying, freezing and critical-point drying techniques.
Studies on large numbers of conidia from the same isolate and from isolates referred to the same species showed the scanning electron microscopy results to be reproducible and provide an objective and accurate method for comparing micromorphological features. The ornamentation types can be of particular value in species identification.     

THE INFLUENCE OF DOSE FRACTIONATION ON RADIATION-INDUCED HAEMOLYSIS OF HUMAN ERYTHROCYTES

In this paper the radioresistance of human erythrocytes to radiation-induced haemolysis was studied by means of the split-dose technique. Human erythrocytes suspended in an isotonic Na-phosphatase buffer, pH7.4 were exposed under air to gamma radiation. Erythrocytes were irradiated with a single dose of 2.7kGy and with the same total dose split into two fractions with an interval between the subsequent exposures. It seems that postradiation processes initiated by the first radiation dose of definite magnitude can lead to an increase in the resistance of erythrocytes to haemolysis under the influence of subsequent dose. The maximal effect of the fractionation (50% decrease of haemolysis) was observed when the first fraction was equal to 0.3–0.4kGy and the interval between exposures was equal to 3h.     

Eutherian mammals from the Early Cretaceous of Mongolia

A collection of eutherian mammals consisting of 39 specimens (teeth and jaw fragments) from the ?Aptian or Albian Khoboor Beds in the Gobi Desert, Mongolia, is described. It contains 3 taxa: Prokenna1estes gen.n., assigned to the Otlestidae Nessov, new rank, with 2 shrew size species; P. trofimovi sp.n. and P. minor sp.n.; a heavily worn larger lower molar which will be described elsewhere. It cannot be excluded that P. trofimovi and P. minor are only sexual morphs within the same species. Prokennalestes and Bobolestes Nessov are possibly the oldest known eutherian mammals, but Prokennalestes is morphologically more primitive than Bobolestes. It has a labial mandibular foramen, 5 premolars and 3 molars, 3 cusps in parastylur region, paracone larger than metacone, unwinged conules, no pre- and posteingula, and lower molars with a 3-cusped talonid, which is narrower than the trigonid, Otlestes and Kennalestes may be derived with little modification from Prokennalestes. Prokennalestes gen.n. is congeneric with Prokennalestes Trofimov and Prozalambdalestes Trofimov, which are both nomina nuda.