Search results for "ANATOMY"
showing 10 items of 3827 documents
Allium nazarenum (Amaryllidaceae), a new species of the section Codonoprasum from Israel
2017
Allium nazarenum, a new species of A. sect. Codonoprasum, is described and illustrated from Israel. Within this species, two well distinct subspecies have been recognized, represented by the subsp. nazarenum and subsp. ramonense respectively. The first one occurs in northern and central Israel, which falls within the Mediterranean bioclimate, while the second one is circumscribed to the Negev desert. Both taxa are diploid with 2n = 16 and are found on various substrata usually in the batha or steppic plant communities. This species shows close relationships with the species belonging to the A. staticiforme group, from which it differs in several relevant diacritic features. Its morphology, …
When less means more: evolutionary and developmental hypotheses in rodent molars.
2012
10 pages; International audience; Tooth number in rodents is an example of reduction in evolution. All rodents have a toothless diastema lacking canine and most premolars present in most other mammals. Whereas some rodent lineages retained one premolar (p4), many others lost it during evolution. Recently, an 'inhibitory cascade' developmental model (IC) has been used to predict how the first molar (m1) influences the number and relative sizes of the following distal molars (m2 and m3). The model does not, however, consider the presence of premolars, and here we examine whether the premolar could influence and constrain molar proportions during development and evolution. By investigating a l…
Allium istanbulense, a new autumnal species of A. sect. Codonoprasum (Amaryllidaceae) from Turkey and its taxonomic position among allied species
2018
Allium istanbulense, a new species of Allium sect. Codonoprasum, is described and illustrated from Istanbul surroundings (European Turkey). It is a late-flowering diploid species (2n = 16), occurring in the undergrowth of oak or pine woods mainly on sandy or incoherent soils. Its morphology, karyology, leaf anatomy, seed micromorphology, ecology, conservation status and taxonomic relationships are examined. A taxonomic comparison with the most allied late flowering species of sect. Codonoprasum and identification keys of the group are also provided.
The evolution of pedipalps and glandular hairs as predatory devices in harvestmen (Arachnida, Opiliones)
2016
Pedipalps are the most versatile appendages of arachnids. They can be equipped with spines (Amblypygi), chelae (Scorpiones), or adhesive pads (Solifugae), all of which are modifications to grasp and handle fast-moving prey. Harvestmen (Opiliones) show a high diversity of pedipalpal morphologies. Some are obviously related to prey capture, like the enlargement and heavy spination of Laniatores pedipalps. Many Dyspnoi, by contrast, exhibit thin, thread-like pedipalps that are covered with complex glandular setae (clavate setae). These extrude viscoelastic glue that is used to immobilize prey items. Comparable setae (plumose setae) have previously been found in representatives of both Eupnoi a…
The role of heterochrony in Schizanthus flower evolution- a quantitative analysis
2021
Abstract Changes in the timing of development within a lineage (heterochrony) have an enormous impact on floral diversification. However, comparative quantitative studies in a broad range of ontogenetic stages are still needed to identify the role of different heterochronic processes shaping diversification patterns. In this study, changes in petal development were compared across species in the genus Schizanthus showing floral diversification mediated by pollinators. In this genus, transitions from bee- to hummingbird- and moth- pollination are associated with lower lip diversification. Variation in size and shape of petals was quantified at key ontogenetic stages by using a traditional an…
Vascular bundle modifications in nodes and internodes of climbing Marantaceae
2020
AbstractNodes are interfaces between stems and leaves. Vascular bundles originate here and elongate into leaves and internodes. In Marantaceae, internodal bundles are highly diverse, including inverted bundles in the climbing genus Haumania. The objective of this paper is to characterize bundle forms, their position across the stem and their connection to leaves and short shoots in Haumania spp. and other unrelated African branch-angle climbers in the family (Hypselodelphys, Trachyphrynium). We question whether bundle inversion is a genus-specific trait in Haumania or related to the climbing growth form. Vascular bundles in internodes are scattered across the stem diameter in a characterist…
A harvestman with elaborate palpal pliers, Thunbergia gretae n. gen. n. sp. from China (Opiliones: Sclerosomatidae: Gagrellinae)
2020
Abstract Based on the unusual characteristics of the male pedipalp and male genital morphology, a new genus and new species of Gagrellinae harvestmen, Thunbergia gretae n. gen. n. sp. (male and female) from Shaanxi Province, China, is proposed. The tibia and tarsus of the pedipalp form elaborate palpal claws, resembling gaspipe pliers, probably used to grasp the legs or the pedipalps of the female during courtship. There is no comparable modification of the pedipalp in the female. The penis lacks wing or sac-like (saccate) elements normally present in Gagrellinae, and the penis base is markedly inflated to form a bulb-like structure harbouring the penis muscle. Two or three opisthosomal ter…
Morphology of spermatheca in Scutelleridae (Hemiptera: Pentatomoidea) and its taxonomic significance
2016
AbstractStructures of spermatheca in 63 species of Scutelleridae (Hemiptera) representing 46 genera and all subfamilies currently recognised in the family were examined and compared. The morphology of three main parts of the spermatheca (receptacle, intermediate part, and spermathecal duct) was described and three main types of spermatheca in Scutelleridae were identified. The taxonomic importance of spermathecal features for the higher classification of scutellerids is discussed.
The probable function of abdominal contractions and liquid drops during the emergence of Zygoptera and Anisoptera (Odonata)
2016
The transition between larval and adult stage in amphibious insects is called emergence. During emergence abdominal contractions and excretion of liquid drops can be observed in several insect orders. Since the function of these processes is not yet known in odonates, this study examines the probable function of abdominal contractions and excretion of liquid drops in Zygoptera and Anisoptera. By subdividing the emergence into 12 successive stages and counting abdominal contractions as well as the excreted liquid drops during these stages we set up a systematic data collection. In all investigated individuals, both processes began in the middle of the entire emergence. We found that abdomina…
Acoustic communication in crocodilians: from behaviour to brain.
2009
Crocodilians and birds are the modern representatives of Phylum Archosauria. Although there have been recent advances in our understanding of the phylogeny and ecology of ancient archosaurs like dinosaurs, it still remains a challenge to obtain reliable information about their behaviour. The comparative study of birds and crocodiles represents one approach to this interesting problem. One of their shared behavioural features is the use of acoustic communication, especially in the context of parental care. Although considerable data are available for birds, information concerning crocodilians is limited. The aim of this review is to summarize current knowledge about acoustic communication in…