Evolutionary changes in craniomandibular shape in the great cats (Neofelis Griffith and Panthera Oken)

Evolutionary shape changes in skull and mandibular anatomy was analysed in 223 specimens of pantherine felids (Neofelis nebulosa, Panthera leo, Panthera onca, Panthera pardus, Panthera tigris, Panthera uncia) compared to a small‐felid outgroup, consisting of 86 specimens of nine different species, using digital surface morphometry on 25 (skull) and 17 (mandible) landmarks. Shape evolution in the pantherine species is complex and nonlinear, and involves both large‐scale and small‐scale shape changes. Shape changes frequently differ among the ingroup species, but the four large Panthera species (leo, onca, pardus, tigris) bear some resemblance to each other. The leopard and jaguar bear the closest resemblance to each other, and several shape changes are common to the lion and tiger, but have probably evolved convergently as a result of large size. The lion has undergone the largest and most numerous shape changes from a small‐felid outgroup. Certain shape changes in the skull and, in some respects, the mandible of the clouded leopard bear resemblance to those in the four large Panthera species. The snow leopard is often regarded as the most primitive of the extant Panthera, and skull and mandibular shape changes often diverge markedly from those observed in the other five ingroup taxa; its overall skull shape is rather similar to the small‐felid outgroup. This indicates that the shape changes in the clouded leopard are convergent with those of the four large Panthera species. Landmark integration showed no significant correlation with molecular phylogeny, chiefly owing to the snow leopard being placed among the four large Panthera species. A traditional phylogenetic topology with the snow leopard as the basal‐most species of Panthera yielded a weak but nonsignificant phylogenetic signal. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 766–778.     

ONTOGENETIC NICHE SHIFT IN THE BRACHIOPOD TEREBRATALIA TRANSVERSA: RELATIONSHIP BETWEEN THE LOSS OF ROTATION ABILITY AND ALLOMETRIC GROWTH

Abstract: Many articulated brachiopods experience marked life habit variations during ontogeny because they experience their fluid environment at successively higher Reynolds numbers, and they can change the configuration of their inhalant and exhalant flows as body size increases. We show that the extant brachiopod Terebratalia transversa undergoes a substantial ontogenetic change in reorientation governed by rotation around the pedicle. T. transversa′s reorientation angle (maximum ability to rotate on the pedicle) decreases during ontogeny, from 180 degrees in juveniles to 10–20 degrees in individuals exceeding 5 mm, to complete cessation of rotation in individuals larger than 10 mm. Rotation ability is substantially reduced after T. transversa achieves the adult lophophore configuration and preferred orientation with respect to ambient water currents at a length of 2.5–5 mm. We hypothesize that the rotation angle of T. transversa is determined mainly by the position of ventral and dorsal points of attachment of dorsal pedicle muscles relative to the pedicle. T. transversa shows a close correlation between the ontogenetic change in reorientation angle and ontogeny of morphological traits that are related to points of attachment of dorsal pedicle muscles, although other morphological features can also limit rotation in the adult stage. The major morphological change in cardinalia shape and the observed reduction of rotation affect individuals 2.5–10 mm in length. The position of ventral insertions of dorsal pedicle muscles remains constant, but contraction of dorsal pedicle muscles is functionally handicapped because dorsal insertions shift away from the valve midline, rise above the dorsal valve floor, and become limited by a wide cardinal process early in ontogeny (<5 mm). The rate of increase of cardinal process width and of distance between dorsal pedicle muscle scars substantially decreases in the subadult stage (5–10 mm), and most of the cardinalia shell traits grow nearly isometrically in the adult stage (>10 mm). T. transversa attains smaller shell length in crevices than on exposed substrates. The proportion of small‐sized individuals and population density is lower on exposed substrates than in crevices, indicating higher juvenile mortality on substrates prone to grazing and physical disturbance. The loss of reorientation ability can be a consequence of morphological changes that strengthen substrate attachment and maximize protection against biotic or physical disturbance (1) by minimizing torques around the pedicle axis and/or (2) by shifting energy investments into attachment strength at the expense of the cost involved in reorientation.     

Cell division study in ‘pollen mother cells’ and ‘pollen grains’ of in vivo and ex vitro plants in Drimiopsis botryoides

The various normal and abnormal stages of meiosis and pollen mitosis of Drimiopsis botryoides are described, and a comparison between naturally propagated in vivo and tissue culture derived ex vitro plants in respect to their cytological behaviour presented. We also describe the floral morphology and investigate the relationship between the floral developmental stages and the progression of microgametogenesis. In total, 33 bivalents are observed in diakinesis, which indicate the diploid number 2n = 66 and this number is cross-checked by a haploid set of n = 33 chromosomes in pollen mitosis. Only 6.8% and 4.9% meiotic abnormalities were recorded on in vivo and ex vitro plants, respectively, which led to the formation of non-viable pollen. Finally, the microspores have to develop into tri-cellular male gametophyte. Only 0.2% pollen grains are found with a micro-nucleus. Though the higher pollen viability was recorded on both in vivo (89.3 ± 4.1%) and ex vitro (92.1 ± 4.6%) plants, but surprisingly the pollen germination rate is extremely low with 13.6 ± 1.74% and 21.3 ± 1.55%, respectively. The present study obviously enriches the cytological database of D. botryoides and may help future research on androgenesis and genetic improvement.     

榆树隐毡蚧各龄若虫和雄成虫形态及其生物学记述(同翅目: 蚧总科: 毡蚧科)

榆树隐毡蚧 Cryptococcus ulmi Tang et Hao是近年来在北京和山西中部发现的一种榆树新害虫。本文首次详细记述和图示了该虫幼期各虫态和雄成虫的形态特征 ;简要报道了其生物学特性 :一年发生 1代 ,以受精雌成虫在树干裂缝内越冬 ,卵胎生 ,每雌产仔 2 3～ 2 5头 ,平均值 35.2头。     

Larval morphology of the lesser housefly, Fannia canicularis

The morphology of all larval instars of Fannia canicularis (Linnaeus) (Diptera: Fanniidae) is documented using a combination of light and scanning electron microscopy. The following structures are documented for all instars: antennal complex; maxillary palpus; facial mask; cephaloskeleton; ventral organ; anterior spiracle; Keilin's organ; posterior spiracle; fleshy processes, and anal pad. Structures reported for the first time for all instars include: two pairs of lateral prominences on the prothoracic segment; additional ventrolateral prominences on the second thoracic segment, and a papilla at the base of the posterior spiracle. Other structures reported for the first time are anterior spiracles in the first instar and a serrated tip on the mouthhook in the second instar. A trichoid sensillum on the posterior spiracular plate, representing a sensory organ otherwise unknown in the Calyptratae, is described in the second and third instars. Results are discussed and compared with existing knowledge on dipteran larval morphology.     

Gene variation and gene flow inOrchis morio (Orchidaceae) from Italy

Data are presented on genetic variation at 27 enzyme loci of the Green-Winged orchid,Orchis morio, in 18 population samples from Italy. The existence in Italy of two subspecies, i.e. subspp.morio andpicta, is not supported by allozyme data. No genetic heterogeneity was found betweenmorio-like andpicta-like samples and specimens. Moreover, morphological transition between the two forms was observed in different Italian populations. The parameters of genetic variability estimated forO. morio populations are consistent with those found among monocotyledon plants, and among those outcrossing, animal-pollinated and with wind-dispersed seeds. Genetic diversity of ItalianO. morio is mostly within populations. Correspondingly, low values of interpopulational genetic distance were found. This appears to be due to high levels of gene flow, which were estimated with different methods. The lack ofO. longicornu from Italian samples, as well as of any hybrid withO. morio (F₁, backcrossed or recombinant individuals) is demonstrated on the basis of genetic data. It is concluded that recurrent reports ofO. longicornu from Italy are due to confusion withO. morio or with otherOrchis species.     

Molecular tests of the proposed diploid hybrid originof Gilia achilleifolia (Polemoniaceae)

Gilia achilleifolia is a putative diploid hybrid species. Hybrid origin was hypothesized based on traditional biosystematicevidence (i.e., morphological, cytological, and crossability data),which may be insufficient to establish genealogical history. Here,phylogenetic analysis of sequence data from the internal transcribedspacer (ITS) regions is used to examine the relationship between theputative hybrid species and its proposed parents. Isozyme variation isassayed to test for genetic additivity in the putative hybrid taxon andmorphological data are analyzed cladistically to evaluate the charactersthat led to the original hypothesis of hybrid origin. The ITS-basedgene tree placed G. achilleifolia in two divergent clades, eachsister to one of the putative parental lineages. Little isozymeadditivity was observed and G. achilleifolia possessed sixunique alleles among 42 alleles observed. However, ITS and isozymetrees differed in their placement of the two lineages of G.achilleifolia; both lineages are closer to a third putative parentin the isozyme tree. Also, G. achilleifolia is intermediate orpolymorphic for all nine morphological characteristics differentiatingthe parental species. Sorting of ancestral polymorphisms cannot easilyaccount for expression patterns of seven of these characters. In ourview, these results fail to distinguish between alternative hypothesesof ancient hybrid origin and divergent evolution, belying the difficultyof detecting ancient hybrids.     

THE MORPHOLOGY AND DEVELOPMENT OF SOME PROMINENTLY STALKED SOUTHERN AUSTRALIAN HALYMENIACEAE (CRYPTONEMIALES,RHODOPHYTA). II. THE SPONGE-ASSOCIATED GENERA THAMNOCLONIUM KUETZING AND CODIOPHYLLUM GRAY1

Three members of the red algal family Halymeniaceae (Thamnoclonium dichotomum (J. Ag.) J. Ag., Codiophyllum flabelliforme (Sond.) Schmitz, and C. decipiens (J. Ag.) Schmitz) are investigated. All are endemic to southern and southwestern Australia, possess basal stalks of substantial size and firmness, and are consistently associated with specific sponge taxa. In each case, the sponges are bonded by collagen-like fibrils to the host cuticle without modifying the algal tissue at the ultrastructural level. Secondary cortication and prominent growth rings occur in the stalks of all three species, and in each the pit plugs between cells become wider, more convoluted and less electron dense with increasing distance from the surface. Such pit plugs are apparently a unique attribute of the stalked Halymeniaceae. The three species share pit plug, sponge association and stalk morphological features but are not otherwise closely related, as they actually represent three distinct genera.