Morphological and genetic diversity of the family Azollaceae inferred from vegetative characters and RAPD markers

Family Azollaceae has seven species with a controversial taxonomy. The identification of species without reproductive structures relies on vegetative characters but some are variable, leading to misinterpretations. The molecular methods may be helpful, but until now, they did not provide a conclusive Azolla taxonomy. Therefore, we studied the family Azollaceae at vegetative and molecular levels. Analysis of vegetative, random amplified polymorphic DNA (RAPD) and combined data showed a comparable grouping of the Azolla species in two main clusters: cluster I, referred to as section Rhizosperma (A. pinnata and A. nilotica) and cluster II, referred to as section Azolla (A. filiculoides, A. microphylla, A. caroliniana and A. mexicana), with the exception of A. rubra, which clustered differently depending on the method. All the Azolla species were distinguished by the 13 polymorphic vegetative characters, the 211 RAPD markers or the combined data, with the latest showing the highest discrimination. The Shannon Index diversity was greater with RAPD (2.276) than with vegetative characters (0.054), highlighting the higher discriminating power of the molecular data. The partitioning of diversity was, as expected, high among species for all the types of data and low within species, with the lowest diversity obtained for morphological data. Both data sets (vegetative and RAPD) allowed the distinction of all the species and their clustering into sections Rhizosperma and Azolla, suggesting this as the most correct for this family. The dendrogram from the combined data was the most accurate, highlighting the benefit of integrating different types of data to study the family Azollaceae.     

Variation in Craniomandibular Morphology and Sexual Dimorphism in Pantherines and the Sabercat Smilodon fatalis

Sexual dimorphism is widespread among carnivorans, and has been an important evolutionary factor in social ecology. However, its presence in sabertoothed felids remains contentious. Here we present a comprehensive analysis of extant Panthera and the sabertoothed felid Smilodon fatalis. S. fatalis has been reported to show little or no sexual dimorphism but to have been intraspecifically variable in skull morphology. We found that large and small specimens of S. fatalis could be assigned to male and female sexes with similar degrees of confidence as Panthera based on craniomandibular shape. P. uncia is much less craniomandibularly variable and has low levels of sexual size-dimorphism. Shape variation in S. fatalis probably reflects sexual differences. Craniomandibular size-dimorphism is lower in S. fatalis than in Panthera except P. uncia. Sexual dimorphism in felids is related to more than overall size, and S. fatalis and the four large Panthera species show marked and similar craniomandibular and dental morphometric sexual dimorphism, whereas morphometric dimorphism in P. uncia is less. Many morphometric-sexually dimorphic characters in Panthera and Smilodon are related to bite strength and presumably to killing ecology. This suggests that morphometric sexual dimorphism is an evolutionary adaptation to intraspecific resource partitioning, since large males with thicker upper canines and stronger bite forces would be able to hunt larger prey than females, which is corroborated by feeding ecology in P. leo. Sexual dimorphism indicates that S. fatalis could have been social, but it is unlikely that it lived in fusion-fission units dominated by one or a few males, as in sub-Saharan populations of P. leo. Instead, S. fatalis could have been solitary and polygynous, as most extant felids, or it may have lived in unisexual groups, as is common in P. leo persica.     

The Dilemma of Choosing a Reference Character for Measuring Sexual Size Dimorphism,Sexual Body Component Dimorphism,and Character Scaling: Cryptic Dimorphism and Allometry in the Scorpion Hadrurus arizonensis

Sexual differences in morphology, ranging from subtle to extravagant, occur commonly in many animal species. These differences can encompass overall body size (sexual size dimorphism, SSD) or the size and/or shape of specific body parts (sexual body component dimorphism, SBCD). Interacting forces of natural and sexual selection shape much of the expression of dimorphism we see, though non-adaptive processes may be involved. Differential scaling of individual features can result when selection favors either exaggerated (positive allometry) or reduced (negative allometry) size during growth. Studies of sexual dimorphism and character scaling rely on multivariate models that ideally use an unbiased reference character as an overall measure of body size. We explored several candidate reference characters in a cryptically dimorphic taxon, Hadrurus arizonensis. In this scorpion, essentially every body component among the 16 we examined could be interpreted as dimorphic, but identification of SSD and SBCD depended on which character was used as the reference (prosoma length, prosoma area, total length, principal component 1, or metasoma segment 1 width). Of these characters, discriminant function analysis suggested that metasoma segment 1 width was the most appropriate. The pattern of dimorphism in H. arizonensis mirrored that seen in other more obviously dimorphic scorpions, with static allometry trending towards isometry in most characters. Our findings are consistent with the conclusions of others that fecundity selection likely favors a larger prosoma in female scorpions, whereas sexual selection may favor other body parts being larger in males, especially the metasoma, pectines, and possibly the chela. For this scorpion and probably most other organisms, the choice of reference character profoundly affects interpretations of SSD, SBCD, and allometry. Thus, researchers need to broaden their consideration of an appropriate reference and exercise caution in interpreting findings. We highly recommend use of discriminant function analysis to identify the least-biased reference character.     

Fine Structure of Sperm of Ekphymatodera thomasoni (Heteroderinae,Nemata)

Fine structure of developing sperm of the monospecific genus, Ekphymatodera, was compared with other Heteroderinae as part of a study to recognize diversity and phylogenetically informative characters within the subfamily. Sperm of Ekphymatodera originate from germ cells connected to a central rachis, a character which is shared with Globodera, but not with other Heteoderinae. In Ekphymatodera, and cyst-forming genera, a layer of cortical microtubules lies just beneath the surface of the plasma membrane. Sperm of Ekphymatodera are unique among Heteroderinae examined by the presence of spiral surface elevations on the filopodia, a character that may prove to be a synapomorphy for Sarisoderini. Fibrous bodies are abundant in spermatids; however, they do not persist in sperm of Ekphymatodera as they do in Meloidodera and Verutus. The male gonad of Ekphymatodera is lined by epithelial cells, which are greatly enlarged near the ejaculatory canal. These enlarged cells contain vesicles with concentric lamellar inclusions, not observed in other genera of the subfamily. Sperm of Heteroderinae are rich in diversity, and examination of additional representative species may indicate new phylogenetically informative characters.     

Cranial variation and taxonomic content of the marbled polecat Vormela peregusna (Mustelidae,Carnivora)

Morphometric variation in 26 characters of 245 skulls of the marbled polecat (Vormela peregusna) was studied across the distribution range. Morphological diversity was low with respect to both the size and the shape of the skull. The sexual size dimorphism of cranial characters in V. peregusna was low compared with other similar-sized mustelids. This finding may be a result of more specialized behaviour, resulting in less intra-specific competition with respect to habitat and food selection. Analysis of the geographic variation of skulls revealed two morphological groups – western and eastern. These groups were treated as distinct subspecies in this study. Nominotypical V. p. peregusna (Güldenstädt, 1770) (syn. sarmatica, euxina) is found in southern and eastern Europe, Asia Minor and Caucasus. The eastern subspecies V. p. koshewnikowi Satunin, 1910 (syn. alpherakii, chinensis, negans, obscura, ornata, pallidior, syriaca, and tedshenika) is found south and east of the Middle East, in Middle and Central Asia and eastward to China. Our data revealed a gradual decrease in the morphological diversity in Vormela skulls from west to east in the distribution range. This phenomenon may be explained by the later origin of the eastern subclusters of the marbled polecat. The pattern of geographic variation revealed in this study may reflect the Pleistocene history of the species range formation, rather than a relationship to climate conditions throughout the modern species range.     

Sexual Dimorphism and Facial Growth Beyond Dental Maturity in Great Apes and Gibbons

The great apes and gibbons are characterized by extensive variation in degree of body size and cranial dimorphism, but although some studies have investigated how sexual dimorphism in body mass is attained in these species, for the majority of taxa concerned, no corresponding work has explored the full extent of how sexual dimorphism is attained in the facial skeleton. In addition, most studies of sexual dimorphism combine dentally mature individuals into a single “adult” category, thereby assuming that no substantial changes in size or dimorphism take place after dental maturity. We investigated degree and pattern of male and female facial growth in Pan troglodytes troglodytes, Pan paniscus, Gorilla gorilla gorilla, Pongo pygmaeus, and Hylobates lar after dental maturity through cross-sectional analyses of linear measurements and geometric mean values of the facial skeleton and age-ranking of individuals based on molar occlusal wear. Results show that overall facial size continues to increase after dental maturity is reached in males and females of Gorilla gorilla gorilla and Pongo pygmaeus, as well as in the females of Hylobates lar. In male Pongo pygmaeus, adult growth patterns imply the presence of a secondary growth spurt in craniofacial dimensions. There is suggestive evidence of growth beyond dental maturity in the females of Pan troglodytes troglodytes and Pan paniscus, but not in the males of those species. The results show the presence of statistically significant facial size dimorphism in young adults of Pan paniscus and Hylobates lar, and of near statistical significance in Pan troglodytes troglodytes, but not in older adults of those species; adults of Gorilla gorilla gorilla and Pongo pygmaeus are sexually dimorphic at all ages after dental maturity. The presence of sex-specific growth patterns in these hominoid taxa indicates a complex relationship between socioecological selective pressures and growth of the facial skeleton.     

Sexual Selection and Dynamics of Jaw Muscle in Tupinambis Lizards

Sexual dimorphism patterns provide an opportunity to increase our understanding of trait evolution. Because selective forces may vary throughout the reproductive period, measuring dimorphism seasonally may be an interesting approach. An increased male head size may be important in intersexual and intrasexual interactions. In Tupinambis lizards, a big head is attributed in part to a large adductor muscle mass. Competition for mating can differ in species with different sex ratio and different degrees of sexual size dimorphism. We examined sexual differences in mass of the pterygoideus muscle, its temporal variation throughout the reproductive period and the relationship between muscle and reproductive condition in Tupinambis merianae and T. rufescens. We characterized sexual size dimorphism and sex ratio in both species. Mature males had larger jaw muscles than mature females in both species, mainly during the reproductive season. The dimorphism in jaw muscle was due to an increase in muscle mass in sexually active males. Seasonal increases in muscle mass and variation between immature and mature individuals suggest that the jaw muscle might be a secondary sexual character. We propose that the pterygoideus muscle may act as a signal of reproductive condition of males because it is associated with testis size and sperm presence. The patterns of sexual dimorphism in jaw muscle in both species were similar; however, the comparison shows how sexual characters remain dimorphic in different competition contexts and in species with different degrees of body size dimorphism. Our results suggest that jaw muscle as sexual character could be influenced by inter- and intrasexual selective pressures.     

Description of Pratylenchus gutierrezi n. sp. (Nematoda: Pratylenchidae) from Coffee in Costa Rica

A lesion nematode, Pratylenchus gutierrezi n. sp., collected from the roots of coffee in the Central Plateau of Costa Rica, is described and illustrated. Its relationships to Pratylenchus flakkensis, P. similis, and P. gibbicaudatus, the only other species of the genus having two head annules, males, or spermatheca with sperm, and an annulated tail terminus, is discussed. Other distinctive characters are its posterior vulva (mean of 80%); its prominently rounded stylet knobs, low head, and subcylindrical tail. SEM observations provide additional details of females and males, especially face views, which show for the first time sexual dimorphism.     

Morphology and anatomy of inflorescence and inflorescence axis in Paepalanthus sect. Diphyomene Ruhland (Eriocaulaceae,Poales) and its taxonomic implications

Paepalanthus sect. Diphyomene has inflorescences arranged in umbels. The underlying bauplan seems however to be more complex and composed of several distinct subunits. Despite appearing superficially very similar, the morphology and anatomy of the inflorescences can supply useful information for the understanding of the phylogeny and taxonomy of the group. Inflorescences of Paepalanthus erectifolius, Paepalanthus flaccidus, Paepalanthus giganteus, and Paepalanthus polycladus were analyzed in regard to branching pattern and anatomy. In P. erectifolius, P. giganteus and P. polycladus the structure is a tribotryum, with terminal dibotryum, and with pherophylls bearing lateral dibotrya. In P. flaccidus, the inflorescence is a pleiobotryum, with terminal subunit, and without pherophylls. Secondary inflorescences may occur in all species without regular pattern. Especially when grown in sites without a pronounced seasonality, the distinction between enrichment zone (part of the same inflorescence) and new inflorescences may be obscured. The main anatomical features supplying diagnostic and phylogenetic information are as follows: (a) in the elongated axis, the thickness of the epidermal cell walls and the cortex size; (b) in the bracts, the quantity of parenchyma cells (c) in the scapes, the shape and the presence of a pith tissue. Therefore, P. sect. Diphyomene can be divided in two groups; group A is represented by P. erectifolius, P. giganteus and P. polycladus, and group B is represented by P. flaccidus. The differentiation is based in both, inflorescence structure and anatomy. Group A presents a life cycle and anatomical features similar to species of Actinocephalus. Molecular trees also point that these two groups are closely related. However, inflorescence morphology and blooming sequence are different. Species of group B present an inflorescence structure and anatomical features shared with many genera and species in Eriocaulaceae. The available molecular and morphology based phylogenies still do not allow a precise allocation of the group in the bulk of basal species of Paepalanthus collocated in P. sect. Variabiles. The characters described and used here supply however important information towards this goal.     

Leaf anatomy as a contribution to the taxonomy of Salacioideae N.Hallé ex Thorne & Reveal (Celastraceae)

The current classification systems recognize Salacioideae as a monophyletic group within Celastraceae. Nonetheless, some divergences exist for genera: in some cases, most species of the subfamily have been included in only two genera; in others, these genera have been subdivided. This study characterizes the leaf anatomy of 31 species of the subfamily Salacioideae as a contribution to identifying them through features that may also help distinguish among genera. Cross-sections of the median region of the leaf blade and of the petiole and dissociated and macerated epidermis were analyzed. Taxonomically relevant anatomical characters include the type of crystals in the parenchymatous tissue (monocrystals in Cheiloclinium and druses in other genera); the presence of laticifers in Cheiloclinium and Tontelea only; the variable form of the petiole vascular system among studied species; the type of stomata (cyclocytic with two concentric circles of subsidiary cells in P. dulcis; anomocytic in T. attenuata, T. fluminensis, and T. leptophylla; laterocytic in C. anomalum and C. hippocrateoides; and ciclocytic in the other species); the sinuosity of the anticlinal walls of the epidermal cells (sinuous in Cheiloclinium and Peritassa, except P. laevigata, and in S. arborea, S. insignis, S. mosenii, S. nemerosa, and S. opacifolia, and straight in all other studied species); the presence of crystalliferous idioblasts in the epidermis of P. dulcis, P. flaviflora, and P. mexiae; and the presence, form, and disposition of sclereids in the leaf blade, which is a highly variable character among the studied species.     

Phylogenetic Re-Evaluation of the Laurencia Complex (Rhodophyta) with a Description of L. Succulenta Sp. Nov. from Korea

Laurencia succulenta sp. nov. (Rhodophyta) is described from Korea. This species exhibits vegetative and reproductive structures typical of the genus, but is distinct from similar species in its epiphytic habitat and the fleshy, robust, thick and subcompressed thalli with basically distichous branching. In addition, it is readily distinguished from the most similar species, such as L. nipponica Yamada and L. okamurae Yamada, by the cystocarps with a somewhat protuberant ostiole. In a phylogenetic analysis of 47 species of the Laurencia Lamouroux complex from various localities around the world based on 49 morphological characters, four major clades (Laurencia, Chondrophycus palisadus (Yamada) Nam group, C. cartilagineus (Yamada) Garbary et Harper group and Osmundea Stackhouse assemblage), each of which forms a monophyletic group, were recognized. Among these, the Laurencia clade is basal to the overall assemblage, and is defined by the vegetative axis with four rather than two pericentral cells. The Osmundea clade is supported by autapomorphic characters for the genus, features associated with spermatangial formation of the filament type and tetrasporangial production from epidermal cells. By contrast, Chondrophycus, a genus characterized by a combination of features (vegetative axis with two pericentral cells, trichoblast-type spermatangial development and tetrasporangial production from pericentral cells), is paraphyletic, and the species were separated into two well-supported clades, the C. palisadus group and C. cartilagineus group. These clades are distinguished from each other by the position of the first pericentral cell relative to the trichoblast, the presence or absence of fertility at the second pericentral cells and number of sterile pericentral cells in the tetrasporangial axis, the pattern of formation of spermatangial branches on trichoblasts, post-fertilization feature associated with the formation time of the auxiliary cell, and, probably, the number of pericentral cells in the procarp-bearing segment. Of these features, the side position of the first pericentral cell in the latter group (a synapomorphy for the C. cartilagineus group plus Osmundea) suggests that the C. cartilagineus group is more closely related to Osmundea than to the C. palisadus group. This cladistic analysis indicates that Chondrophycus is not monophyletic, suggesting that the C. palisadus group should be separated from Chondrophycus at the genus level. Based on this result, Palisada (Yamada) stat. nov. is proposed for the group, together with an emendation of the generic delineation of Chondrophycus, and relevant nomenclatural changes for several Chondrophycus species are also included. In addition, Corynecladia J. Agardh is reinstated for the type species L. clavata Sonder.     

沙芥属植物叶片的气孔特征研究

观察了沙芥属（Pugionium Gaertn.）3个种：沙芥（P.cornutum (L.)Gaertn.）,距果沙芥（P.calcaratum Kom.）和斧翅沙芥（P.dolatum Maxim. var. dolabratum）的子叶和真叶表皮特征及气孔指标,并进行了差异显著性分析。结果表明：沙芥属植物表皮形状多为无规则形,上、下表皮均具有气孔,气孔类型均为不等细胞型。气孔保卫细胞呈肾形,内壁加厚,但加厚程度不同,斧翅沙芥＞距果沙芥＞沙芥。气孔缝呈纺锤形,气孔均下陷;气孔日开闭规律均呈双峰曲线。斧翅沙芥和距果沙芥的气孔性状具有较大的相似性,但这两个种与沙芥的气孔性状存在明显差异,说明沙芥属植物叶片气孔稳定性状和形态可以作为种质资源鉴定和评价的重要微观特征。     

ENDOMORPHIC AND ECTOMORPHIC CHARACTERS IN PELECYPHORA AND ENCEPHALOCARPUS

Boke , Norman H. (U. Oklahoma, Norman.) Endomorphic and ectomorphic characters in Pelecyphora and Encephalocarpus. Amer. Jour. Bot. 46(3) : 197-209. Illus. 1959.—Outstanding ectomorphic characters of Pelecyphora valdeziana include its small size; pectinate, hairy spines; broad, truncate, floral buds; dehiscent, berry-like fruits; and black, tuberculate seeds. The leaves are vestigial, and although the areole meristem originates on the adaxial face of the tubercle primordium, it is soon elevated to the summit by intercalary growth. The first primordium of the single, elliptical series of spines is initiated immediately in front of the rudimentary leaf. Others form in acropetal sequence on either side of the areole meristem. The last ones form across the areole, leaving a meristem, which may be floral or vegetative, on the anterior side. Whether areoles of P. valdeziana can be considered dimorphic is doubtful. However, they approach the type of dimorphism found in Epithelantha. Pelecyphora aselliformis has acuminate floral buds; dry, papery fruits; and brown, curved, reticulate seeds. The leaves are reduced almost to extinction. The areole meristem becomes separated into spiniferous and axial portions early in ontogeny, but the 2 parts remain connected by a band of trichomes, which probably represents a vestigial groove. The axial meristem may be reproductive or vegetative. The sequence of spine initiation in P. aselliformis is unusual in that it begins at the anterior side of the spiniferous meristem and proceeds toward the posterior side. Areoles in this species are clearly dimorphic, much as in the mammillarias, but the vestigial groove is reminiscent of Coryphantha and related genera. Although adult specimens of Encephalocarpus strobiliformis bear scale-like tubercles, which are very different from the laterally compressed tubercles of P. aselliformis, their flowers, fruits, and seeds are almost identical. The two species share the same type of areole dimorphism, including the vestigial groove. Tubercles on seedlings and young branches of E. strobiliformis are prismatic rather than scale-like. Since they tend to be laterally compressed at the summit and bear elliptical areoles with many more spines than the adult, they resemble seedling tubercles of P. aselliformis. Tubercles on adult specimens likewise resemble each other in the structure of the epidermis and hypodermis. It does not seem possible that P. valdeziana can be retained in the genus Pelecyphora. If seed structure has any systematic value, the species belongs in or near the genus Thelocactus, to which it was assigned by Bravo. Pelecyphora aselliformis and Encephalocarpus strobiliformis, on the other hand, share so many important characters that they could well be considered cogeneric. Both seed structure and the rudimentary grooves on the tubercles suggest that their affinities may lie with certain coryphanthas or mammillarias rather than with Ariocarpus and Epithelantha.     

The high-affinity phosphodiesterase PcPdeH is involved in the polarized growth and pathogenicity of Phytophthora capsici

The cAMP signaling pathway has been shown to be important in controlling morphological changes and pathogenicity in plant pathogens. In the present study, we identified PcPdeH, a gene encoding a high-affinity phosphodiesterase (PDE), which is a key regulator of the cAMP signaling pathway. To elucidate the function of PcPdeH, PcPdeH-knockout mutants were obtained using a type II CRISPR/Cas9 system in Phytophthora capsici. The knockout transformants of PcPdeH showed vegetative growth defects and abnormal cyst germination. Infection assays indicated that compared with the wild type, PcPdeH-knockout mutants showed significantly reduced virulence on pepper and tobacco leaves and exhibited increased (1.5-2-fold) cAMP levels relative to the wild-type and CK strains. Based on these phenotypic features, we propose that PcPdeH is crucial for vegetative growth, cyst germination and pathogenicity in P. capsici.     

Reassessment of Paleotachina Townsend and Electrotachina Townsend and their removal from?the?Tachinidae (Diptera)

The monotypic genera Paleotachina Townsend, 1921 and Electrotachina Townsend, 1938 were originally described as fossils in amber but were later discovered to be inclusions in copal. Both taxa were originally assigned to the Tachinidae (Diptera) and this placement has continued to the present day. The holotypes of the two type species, P. smithii Townsend and E. smithii Townsend, were examined and the following taxonomic and nomenclatural changes are proposed: Paleotachina is transferred to the Muscidae and placed in synonymy with Aethiopomyia Malloch, 1921, syn. n.; P. smithii Townsend, type species of Paleotachina, is synonymized with Aethiopomyia gigas (Stein, 1906), syn. n.; Electrotachina is transferred to the Sarcophagidae and placed in synonymy with Dolichotachina Villeneuve, 1913, syn. n.; E. smithii Townsend, type species of Electrotachina, is recognized as a valid species of Dolichotachina comb. n. Images of the holotypes of P. smithii and E. smithii are provided and features that have helped place these copal inclusions in their new combinations are discussed.     

Morphometric study and sexual dimorphism analyses in an Iranian population of Scorpio maurus (Arachnida: Scorpionidae)

Natural selection and sexual selection are cardinal factors in shaping the body of animals such as scorpions. Scorpio maurus (Scorpiones: Scorpionidae) has a worldwide distribution. Sexual dimorphism has been reported from this species in a study in Egypt. Morphometry is used to determine the sexual dimorphism between the two sexes. In the current study, scorpions were collected from six locations of the southern and northern provinces of Fars, Iran. In this study, 53 morphological characters of 15 specimens of each sex of Scorpio maurus were studied based on statistical analyses; however, dimorphism was only observed in 21 morphological characters, including chelicerae and carapace length, pedipalp characters, width of the second segment of metasoma, telson and pectin length, number of left pectin teeth, and some of the leg''s segments. It means that these characters are in the control of sexual and natural selection. This study was performed for the first time on Scorpio maurus species in Iran.