Phylogenetic relationships among the lepidopteran and trichopteran suborders (Insecta) from the embryological standpoint1

Adopting the cladistic method in comparative embryology, 27 embryonic characters were analyzed to reconstruct the phylogenetic relationships among the lepidopteran and trichopteran suborders, viz., Annulipalpia, Integripalpia, Zeugloptera, Dacnonypha, Exoporia, Monotrysia, and Ditrysia. The resultant cladogram is basically coincident with that proposed by Kristensen . The order Trichoptera and Lepidoptera constitute a monophyletic group on the basis of one synapomorphy, the presence of well developed silk glands in embryos. The Trichoptera are separable from the Lepidoptera by the states of four characters. The Trichoptera, as a whole, are quite homogenous, and embryological data provide no rational ground for the separation of this order into the Annulipalpia and Integripalpia at a subordinal level. On the contrary, the embryonic development of the Lepidoptera becomes divergent from the most primitive condition to a specialized one according to suborders. The Zeugloptera are the sister group of all other Lepidoptera, because they share two apomorphies with the latter. The Dacnonypha are the most primitive next to the Zeugloptera, and have a sister-group relationship with the Exoporia + (Monotrysia + Ditrysia), being held together with the latter by five synapomorphies. Although the Exoporia retain almost as many plesiomorphic characters as the Dacnonypha, they have a sister-group relationship with the Monotrysia + Ditrysia, as inferred on the basis of two synapomorphies. The Monotrysia and Ditrysia have a sistergroup relationship, and are the most advanced groups in the Lepidoptera judging from their shared acquisition of many apomorphic characters.     

Evolution of ommatidium structure in the Trogidae (Coleoptera)

Abstract. Ommatidium lens structure in the Trogidae and the monotypic Glaresidae is studied. Three types (eucone, duocone and exocone) are found in the Trogidae [and most Scarabaeoidea]; only the eucone type occurs in the Glaresidae. Evidence is presented that evolution of ommatidium type in the Trogidae has proceeded from a basic eucone type such as that in extant Glaresis and Trox , to a more derived eucone as in Polynoncus and some species of the Omorgus subgenera Omorgus and Afromorgus , through various states of the duocone type as in the remainder of the species belonging to these subgenera, to the highly evolved exocone ommatidium found in the monobasic Omorgus (Haroldomorgus). An improvement in optics of the duocone and exocone over the eucone may have driven the evolution of these types. Ommatidium structure does little to confirm or refute proposed relationships among trogid taxa but does clearly indicate the path of evolution of the different lens systems in the Trogidae and illustrates the probable course of evolution of ommatidium structure in the Scarabaeoidea.     

Mosaic evolution, mosaic selection and angiosperm phylogeny

STEBBINS, G. L., 1984. Mosaic evolution, mosaic selection and angiosperm phylogeny. Mosaic evolution is a general pattern of evolutionary change, and is expected on the hypothesis that rvolution is basically opportunistic rather than determinate. It is most often exemplified by constancy with respect to one set of characters over a given period of time, accompanied by more or less rapid change with respect to other characteristics of the same organisms. To the extent that the characters involved are functional and adaptive, mosaic evolution must be guided by mosaic selection. A survey of character differences between species belonging to 59 of the largest genera found in the California flora indicates that mosaic selection has played an important role in the evolution of modern species of angiosperms. Mosaic evolution has also taken place with respect to dinerent chromosomal and biochemical characteristics, as is evident from comparisons between morphological, chromosomal and biochemical differences. When the widespread Occurrence of mosaic evolution and of mosaic selection are recognized, two general principles emerge: the primitive or advanced nature of individual character states cannot be deduced solely on the basis of their correlation or association with other character states which are believed to be primitive or advanced; mosaic selection provides a strong basis for the conclusion that natural selection is the most basic process that converts changing population-environment interactions into evolutionary change.     

Comparative osteology and relationships of the Umbridae (Pisces: Salmoniformes)

The phylogenetic relationships of the five living species of umbrids are examined through a comparative osteological study based on a series of cleared-and-stained specimens of each species. The Umbridae appear to be strictly monophyletic. In addition, for 45 characters, the outgroup Esox shares one character-state with at least one umbrid species, while two or more umbrid species share the other state. Assuming that the states shared with Esox are primitive for the Umbridae, the hypothesis that Dallia is more closely related to Umbra than to Novumbra is supported by compatibility and Wagner-tree analysis of the data. Thirteen derived characters are shared by Dallia and Umbra , 20 more are shared by the three species of Umbra , and four more by U. limi and U. pygmaea. Eight characters are considered likely to have undergone reversal or parallel evolution.     

STUDIES OF PALEOZOIC MARATTIALEANS: NEW SPECIES OF SCOLECOPTERIS (MARATTIALES) FROM THE PENNSYLVANIAN OF NORTH AMERICA

Two new species of the late Paleozoic fern Scolecopteris (Marattiales) are described and their relationships within the genus are discussed. Scolecopteris charma sp.n., from Steubenville, Ohio (Duquesne Coal, Upper Pennsylvanian), is similar to species in the Oliveri group, while S. gnoma sp.n. from Providence, Kentucky (Baker Coal, Middle Pennsylvanian), compares favorably with the Latifolia species group. Scolecopteris gnoma is most similar to S. fragilis but differs in its smaller synangia and spore type. S. charma appears generally similar to S. iowensis because of its large pedicel and histologically undifferentiated walls, but differs in a number of characters such as vasculature and spore type. Despite its occurrence late in the Pennsylvanian, S. charma is thought to possess a number of primitive character states (large trilete spores, vascularized pedicels, flat pinnules with downturned margins). Using the same criteria for the much older S. gnoma, we note a number of relatively apomorphic character states (small monolete spores, unvascularized pedicels, extended pinnule margins). An outgroup analysis of species-level characters of Scolecopteris gives a better concept of primitive versus derived traits in marattialean and other ferns. Genera in the Paleozoic fern orders Filicales (Ankyropteris) and Zygopteridales (Corynepteris, Musatea) were chosen as outgroups, and the comparisons support suggestions for the polarity of several important characters. Some of these agree with previously proposed evolutionary polarities based on the geological occurrence of marattialean ferns.     

On the affinities of the burrowing asps Atractaspis (Serpentes: Atractaspididae)

An analysis is presented of a sample of Atractaspididae ( sensu McDowell) plus Macrelaps, Aparallactus, Apostolepis, Elapomorphus, Homoroselaps and six genera of African elapids in respect of squamation, reproductive organs, skull, head muscles and vertebrae. Homoroselaps is linked with the African Elapidae and is returned to that family. Scattered special resemblances to atractaspids are interpreted as homoplasies. Some interrelationships of the African elapids are suggested. The South American Apostolepis and Elapomorphus represent a separate, possibly related, lineage at the same grade level as the African Atractaspididae. Macrelaps and Aparallactus are transferred to the Atractaspididae. Atractaspis emerges as a low grade but highly divergent member of the family. Macrelaps is the most primitive. The other taxonomic units are completely resolved with, however, the anomaly of reversal to the seemingly primitive states of six characters in four lineages (six genera). The Atractaspididae, Apostolepis and Elapomorphus are regarded as low grade members of the Caenophidia. It is suggested that early in the history of the caenophidian lineage a venom apparatus was acquired, prior to the major radiation of the group. Many descendent lineages show regression of the venom apparatus.     

Origins of Hippopotamidae (Mammalia, Cetartiodactyla): towards resolution

The old debate on hippopotamid origins is still unresolved, balancing between two main phylogenetic hypotheses: origins within the Anthracotheriidae vs. origins within the Tayassuidae. The characters used in the literature to support one, the other, or both hypotheses were re-examined in light of a better known primitive hippopotamid morphology. A cladistic analysis was performed on the basis of these characters. On the one hand, although many features similar in hippopotamuses and anthracotheres appear to have evolved in parallel, the family Anthracotheriidae remains the best putative hippopotamus stem group on the basis of the reviewed characters. However, the precise identification of a stem group within this family is still uncertain. On the other hand, the lineage proposed in the tayassuid hypothesis should not be retained, being mostly based on some incorrect observations and without taking into account the derived or primitive nature of the features. The anatomic similarities seen between modern peccaries and Hippopotamus amphibius are the results of convergences between advanced species of both families.     

Glaresidae, a new family of Scarabaeoidea (Coleoptera) to accommodate the genus Glaresis Erichson

Abstract. The genus Glaresis does not share any demonstrable apomorphs with any other group of Scarabaeoidea. Detailed examination of twelve adult characters and their comparison with those in all the primitive Scarabaeoidea resulted in a well-defined genus that is primitive in virtually all its characters. It is concluded that Glaresis lies near the base of the ancestral stock from which most scarabaeoids evolved. Since the genus cannot be accommodated in an existing higher taxon we propose that the monotypic tribe Glaresini Semenov & Medvedev (the genus Afroglaresis Petrovitz is here synonymized with Glaresis) , be accorded family status.     

Parallel tion in the context of character analysis

For the establishment of polarity of character transformation prior to phylogenetic analysis, various logical and biological criteria are discussed; some are rejected on grounds of liability to systematic error, circularity or unwarranted assumptions aboutParallel tion is used as a non-polar term, with forward and reverse to indicate polarity. A computer program for the detection of parallel tion is described which takes taxa in groups of four. The characters, with two derived: two primitive states or three derived: one primitive state, are listed according to the distribution of states over the four taxa. To each of the 15 phylogenies there corresponds a compatible pair of character patterns. Discordant 2: 2 patterns are unconditionally incompatible (Le Quesne test failure), discordant 3: 1 patterns are incompatible conditional upon correct scoring of polarity. For any putative phylogeny the concordant and discordant characters are identified. In cases of competing alternatives these character sets have to be weighed against one another. Character weighting is discussed; it is argued that it is the individual character transformation which should be weighted, in each direction separately.     

Huehuecuetzpalli mixtecus gen. et sp. nov: a basal squamate (Reptilia) from the Early Cretaceous of Tepexi de Rodríguez,Central México

Huehuecuetzpalli mixtecus gen. et sp. nov. is characterized by a combination of characters unlike those of any of the previously described Late Jurassic or Early Cretaceous lizards. It has most of the synapomorphies common to modern squamates, but still retains primitive features rare in living taxa. Autapomorphic characters include an anteroposteriorly elongated premaxilla that results in the elongation of the snout and the apparent retraction of the external nares. A small rounded postfrontal and a parietal foramen on the frontoparietal suture suggest affinities with iguanians, but the retention of divided premaxillae, amphicoelous vertebrae, thoracolumbar intercentra, entepicondylar foramen, and a second distal tarsal supports the hypothesis that Huehuecuetzpalli has a more basal position relative to the extant squamates. Although its appearance is late in the fossil record of lizards, Huehuecuetzpalli is the first report of a basal squamate. It provides important information on early transformation of characters in lizard evolution. Many primitive characters present in some modern squamates are usually explained by paedomorphosis; however, these characters are common in early lizards suggesting that derived states may have been fixed later in lizard evolution. If Huehuecuetzpalli is an iguanian, then it would be the earliest known representative of this lineage and extends their fossil record into the Albian. This paper presents an extensive review of the characters and character states used in previously published cladistic analyses of the Squamata.     

The evolution of diagnostic characters of wing venation in representatives of the subfamily Myrmeciinae (Hymenoptera,Formicidae)

Problems of the formation of a complex of diagnostic characters that determine taxa of the subfamily Myrmeciinae are discussed. A comparative analysis of morphological data on the recent and extinct Myrmeciinae was performed. The wings of recent and Paleogene representatives of Myrmeciinae have different complexes of diagnostic characters. The wings of extinct Myrmeciinae have intermediate features of venation and demonstrate more primitive states of some characters as compared to those of recent poneromorphs.     

Phylogenetic and Morphological Evolution of Green Euglenophytes Based on 18S rRNA

Green euglenophytes are a group of eukaryotes with ancient origin. In order to understand the evolution of the group, it is interesting to know which characteristics are more primitive. Here, a phylogenetic tree of green euglenophytes based on the 18S rRNA gene was constructed, and ancestral states were reconstructed based on eight morphological characters. This research clarifies the phylogenetic relationships of green euglenophytes and provides a basis for the study of the origin of these plants. The phylogenetic tree, which was constructed by Bayesian inference, revealed that: Eutreptia and Eutreptiella were sister groups and that Lepocinclis, Phacus, and Discoplastis were close relatives; Euglena, Cryptoglena, Monomorphina, and Colacium were closely related in addition to Trachelomonas and Strombomonas; and Euglena was not monophyletic. An ancestral reconstruction based on morphological characters revealed seven primitive character states: ductile surface, spirally striated, slightly narrowing or sharp elongated cauda, absence of a lorica, chloroplast lamellar, shield or large discoid, pyrenoid with sheath, and with many small paramylon grains. However, the ancestral state of the length of the flagellum could not be inferred. Euglena and Euglenaria, which both possessed all of the ancestral character states, might represent the most ancient lineages of green euglenophytes.     

ROOTING PHYLOGENIES OF PROBLEMATIC FOSSIL TAXA; A CASE STUDY USING CINCTANS (STEM-GROUP ECHINODERMS)

Abstract:  Extinct clades whose higher-level relationships are problematic or disputed pose a particular problem for phylogenetic analysis because of the difficulty of establishing a convincing root. Cinctans are a problematic group of primitive preradiate echinoderms whose morphology is so distinct that few characters can be usefully homologized with any other group. Here we use a two stage approach, first constructing an unrooted network using the totality of phylogenetically informative characters in which individual plates are homologized, and then determining the root position with a much smaller set of recast characters that can be polarized by outgroup and/or ontogenetic criteria. Furthermore, when rooting is based on stratigraphic criteria the same two major derived clades are identified, although basal relationships are somewhat different. We contend that the congruence of results obtained using our various approaches provides confidence that we have correctly rooted the cladogram. A revised taxonomy for Cincta is presented.     

Vegetative anatomy and morphology of Amentiferae

Some of the important vegetative characters of amentiferous families described in research papers concerned with interfamilial relationships and published since 1947–1948 are briefly summarized. Important conclusions by the writers are also reviewed. Thus, Bataceae are considered derivatives of the Centrospermae ; Betulaceae, Casuarinaceae, and Ulmaceae are hamamelidaceous derivatives; Garryaceae and Cornaceae are closely related; and Julianiaceae and Anacardiaceae are plausible relatives. A more extensive tabulation of vegetative characters of essentially all amentiferous and ranalean families and Dilleniaceae is also presented, and the data are utilized to compare the percentages of advanced and primitive characters in these same taxa. The logic for considering trends whose evolutionary directions were initiated previous or incidental to angiospermous origin as more valid than other evolutionary trends is offered. The following principal conclusions are based upon the analysis of the tabulation: (1) the Amentiferae have sufficient advanced vegetative characters to preclude consideration of them as earliest angiosperms or their direct derivatives unless a large number of primitive features of other sorts offers strong counter evidence; (2) they also have sufficient primitive characters to discount the concept that they are highly evolved; (3) most Amentiferae clearly possess many more advanced vegetative characters than do most Magnoliales, Laurales, Trochodendrales, or Dilleniaceae ; and (4) relationships of several Amentiferae to various, unrelated angiospermous families have been demonstrated.     

Cladistic Analysis of Sphagnum in Northeast China

This paper deals with the phylogenetic relationships in Sphagnum using the Wagner Groundplan-Divergence method. The main principle of the Wagner GPD method is grouping based on synapomorphy derived from outgroup comparison and ontogenetic analysis whenever possible. We make use of 21 available characters from gametophytes, estimate plesiomorphic conditions on the principle that characters found in the group under study and in most or all members of related groups are plesiomorphic, while those found only within the group are apomorphic, and finally arrange taxa according to shared derived features. In the Wagner tree diagrams, all characters can be placed on a Wagner tree so that the various relationships in the genus Sphagnum can be visualized. The results were as follows: 1. The genus Sphagnum can be divided into six sections, i.e. Sphagnum, Squarrosa, Acutifolia, Cuspidata, Subsecunda and Polyclada. They are almost consistent withe those derived from classical and numerical taxonomy of Sphagnum. 2. In Wagner tree diagrams, Section Sphagnum and Sect. Squarros were branched earlier, so they are primitive and the other four sections were last branched, so they are derived. Sphagnum magellanicum is a rather primitive species, whereus S. girgensohnii andS. fimbriatum are rather advanced ones in the 14 species of Sphagnum investigated.     

苔草属复序苔草亚属十四种植物叶片的解剖学研究

选择中国复序苔草亚属6组4亚组的代表植物14种,进行了叶片解剖学研究,观察了其横切面 和表皮特征,证明上述特征在各类群之间存在差异,具有一定的系统学意义。这14种植物叶片的横切 面和表皮都具有一些原始的性状,表明复序苔草亚属中的植物可能在苔草属中是较原始的。在所观察 的植物中,Sect．Polystachyae植物叶片解剖学特征比较一致,说明此组的建立比较合理;而Sect．Indicae 组已有明显分化,尤其是Carex scaposa C．B．Clarke和C．densifimbriata Tang et S．Y．Liang 与其它植物明显不同,而且其外部形态特征在复序苔草亚属中也比较独特,因此赞成将它们及其近缘类群做为一个组而非亚组。     

The trigeminal jaw adductors of primitive snakes and their homologies with the lacertilian jaw adductors

The trigeminal jaw adductor musculature of anilioid snakes is analysed. The group is characterised by primitive characters, viz. the presence of an extensive bodenaponeurosis and of a quadrate aponeurosis. A temporal tendon gives rise to superficial (lb) fibres which are not observed in other snakes: this may be a primitive or a derived feature.
Jaw adductor muscles in snakes are usually subdivided following their relative position in an antero–posterior direction. Lacertilian jaw adductors are subdivided in a transverse plane. A detailed comparison of the anilioid and primitive lacertilian jaw adductors establishes correspondences (homologies) of parts in the transverse plane in both groups. These homologies are corroborated by innervational patterns.
Platynotan lizards are widely accepted as potential snake ancestors. A comparison of homologue jaw adductors shows different evolutionary trends to characterise platynotan lizards and snakes. Theoretically, these findings do not rule out primitive platynotan lizards as snake ancestors. On the basis of the structure of jaw adductors, snakes are to be derived from a primitive lacertilian pattern, be it platynotan or not.     

Leaf Anatomy of Fourteen Species in Carex Subgenus Indocarex (Cyperaceae)

Among the subgenera of the genus Carex, the subgenus Indocarex has been seldom studied in any respects, Its systematic position and its subdivision are still disputable. Leaf anatomy of 14 species in the subgenus lndocarex from China was studied. The anatomical characters are proved to be systematically valuable. (1) Characters of lamina transverse section: All leaves of these 14 species are dorsiventral. The outline mostly V-shaped, occasionally flat or nearly flat, with adaxial lateral rib in each half of lamina and some of them flanged. The cells of adaxial surface larger than those of abaxial surface, and the epidermal cells over veins usually smaller than others. Air-cavities between vascular bundles are well developed, and bulliform cells also well developed in most taxa. The vascular bundles are collaterai, bundle sheaths double-layered, and the outer sheath parenchymatous and the inner sheath fibrous. (2) Characters of lamina epidermis: The shape of the cell on both surfaces is generally rectangular, and the anticlinal wall of epidermal cell sinuous; stomata is paracytic, elliptic to oblong, rarely sub-circular; prickles occur on adaxial surfaces of certain species; papillae are only obvious on abaxial surface of C. moupinensis Franch. The characters of transverse section and epidermis of leaf blades of these 14 species differ from each other to certain degree, and closely related species are similar in anatomical characters. The anatomical characters of lamina are of value for classification at specific and sectional level of the subgenus Indocarex. Despite of the variation of these characters among species, a certain num ber of characters appears to be shared by the members of the subgenus, and some of the common characters are primitive. In addition, some gross morphological characters are common and primitive also. Therefore, the subgenus Indocarex may be primitive in the genus Carex. The anatomical and morphological characters of C. scaposa C. B. Clakre and C. densifimbriata Tang et Wang ex S. Y. Liang are distinct. The two species and their allies should be treated as section instead of subsection. The three species in the sectionPolystachyae share some anatomical characters and comprise a coherent group.