Development of the Snout of the Australian Lungfish Neoceratodus forsteri (Krefft, 1870), with Special Reference to Cranial Nerves

Abstract The anatomy and embryology of the dipnoan snout and olfactory organ play a major role in the discussion about the phylogenetic position of Dipnoi and the question of ancestry of Tetrapoda. This is primarily due to the fact that an internal nostril is regarded as an important preadaptive organ of the ancestors of tetrapods. Two conflicting scenarios of phylogenetic change were proposed in favour of different hypotheses of relationship. One emphasizes the similarities between Dipnoi and Chondrichthyes concerning this complex of characters. The other supports the idea of a close relationship of Dipnoi and Tetrapoda and a common origin of a ‘choana’ from the posterior external nostril of fishes. Accordingly, there is need for a detailed embryological and anatomical study which could help to clarify homologies and the basis of character evaluation. This, in the first place, concentrates on Neoceratodus forsteri. A plate reconstruction of the larval head provides many new insights which are important for comparison with the lepidosirenid lungfishes Protopterus and Lepidosiren and with other vertebrate taxa. The value of the peripheral nervous system as a topographical reference is critically reviewed. The results support the hypothesis that lungfish form a ‘primitive’ teleostomate group, closely adjoining Chondrichthyes in many characteristics of the snout formation. The relations between cranial nerves in the snout and the developing nasal sac, however, do not support the conclusion that the recent selachian condition is the exceptional ancestral character state of the lungfish snout. Dipnoi lack a ‘choana’, but nevertheless a closer relationship to tetrapods is not excluded. A vestigial and transitory naso-buccal connection in larvae of Neoceratodus might indicate such common ancestry, but has a completely different functional significance among fishes. It is shared with several plagiostomes and is, therefore, probably not useful as a synapomorphy of Dipnoi and Tetrapoda.     

The morphology of the lung of the African lungfish,Protopterus aethiopicus

Summary The lung of the African lungfish (Protopterus aethiopicus) is paired, long and cylindrical. It is situated on the dorsal aspect of the coelomic cavity ventral to the ribs. Much of the gas exchange tissue is found in the proximal aspect of the lung with the caudal part largely taken up by a centrally situated air-duct with a few large peripherally located alveoli. Interalveolar septa, arranged at differing hierarchical levels from the air-duct, subdivide the lung into alveoli, the gas exchange compartments. The alveolar surface is covered by some cells characterized by microvilli on their free surface, while others are devoid of such structures. The general organization of the lung of Protopterus aethiopicus is similar to that of the other genera of Dipnoi, Neoceratodus and Lepidosiren, with the interalveolar septa increasing the surface area for gas exchange through pulmonary compartmentation. The abundant septal smooth muscle fibres and elastic tissue may contribute to the physiomechanical compliance of the lung. The undifferentiated alveolar pneumocytes and the double capillary system, observed in Protopterus, in general appear to characterize the very primitive lungs of the lower air-breathing vertebrates.     

Comparative studies on the teliospore morphology and ontogeny ofSpumula serispora,spec. nova,andRavenelia texensis (Uredinales,Raveneliaceae)

A new rust fungus,Spumula serispora, is described. The morphology of the teliospores and the telia was studied. In the teliospores ofS. serispora andS. quadrifida, the type species of the genus, sterile cells could be found, which are comparable to apical cells of otherRaveneliaceae. Similar sterile cells were also present in the telial heads ofRavenelia texensis. The ontogeny of the teliospores ofS. serispora and the teliospore heads ofRavenelia texensis was studied and compared. In both species the ontogeny of the spores heads was similar. InR. texensis hygroscopic cysts sustaining the spore heads were produced by division and not by conversion of basal sterile cells of the teliospore heads.Part 114 of the series Studies inHeterobasidiomycetes.     

THE BIOLOGY OF THE LOBE-FINNED FISHES

1. Interpretation of structural evolution in a group such as the Sarcopterygii requires consideration of a combination of all possible functions, rather than single functions. 2. The Dipnoi are probably more closely related to the Crossopterygii than to other groups of fishes. The Sarcopterygii are a ‘natural’ group. Certain characters in common between the elasmobranchs and the Dipnoi or Coelacanthini seem to be the result of convergent evolution. 3. Evolution of the skull, in connexion with both respiratory and feeding mechanisms, has resulted in extreme specialization in all Sarcopterygii. The crossopterygian intracranial kinesis has evolved from an earlier mobility between the skull and neck and is adapted for increasing the power of the bite and for enclosing the prey from both above and below, in addition to other factors. Adaptive radiation is seen in the feeding mechanisms of all forms. The evolution of the Amphibia proceeded through elongation of the anterior division of the skull (which is not correlated with any changes in brain morphology) and loss of the kinetic mechanism in this sequence is at least partially associated with improved buccal pumping mechanisms for lung ventilation. 4. Adaptive radiation of the respiratory system in Dipnoi shows a progressive increase in the use of aerial respiration. The aquatic condition seen in Neoceratodus is probably secondary. Comparison of the three living genera shows a striking correlation between respiratory physiology and habit. There is little indication of reduction of the branchial respiratory system in known Rhipidistia, in which respiration was probably primarily aquatic. In Dipnoi and Rhipidistia, evolution of the lung allowed a partial control of the hydrostatic properties of the body. In coelacanths, aerial respiration was abandoned, except in certain secondarily freshwater forms, and the single lung is modified as an organ of hydrostatic balance. These changes are reflected in the over-all body proportions. 5. Locomotion in Sarcopterygii (except the coelacanths Laugia and Piveteauia) is adapted for contact with the substrate in relatively shallow water in most cases. Adaptive radiation of the locomotor apparatus is seen with respect to the relative roles and functions of the paired and unpaired fins, over-all body shape, caudal fin shape, and absolute size. An important function of the pectoral fins in advanced Rhipidistia was in supporting the body in shallow water and thus aiding lung ventilation. 6. Aestivation is an early feature of dipnoan biology, but was not evolved in Rhipidistia. The common faculty of urea production via the ornithine cycle and urea retention in coelacanths and dipnoans are adaptations to conditions in which the body tissues may become dehydrated (salt water and desiccation, respectively). The common pattern of nitrogen metabolism seems to have evolved during a marine phase in sarcopterygian evolution. 7. There is evidence that the earliest members of all sarcopterygian lines included marine forms. However, the subsequent major radiations of Dipnoi and Rhipidistia occurred in fresh waters. The distribution of Sarcopterygii was entirely tropical. The late Palaeozoic distribution of the freshwater forms seems to offer evidence for the occurrence of Continental Drift. Coelacanths were primarily coastal fishes. 8. The evolution of a major group of organisms requires a different pattern of evolutionary change than that by which adaptive radiations are produced. It evolves the structural and temporal correlation of modification in a number of different functional systems rather than the separate modification of each system without reference to other systems. 9. The first tetrapods evolved in a highly seasonal swampy environment on the shores of inland lakes or rivers, in permanently moist conditions.     

The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi)

Lungfish, or dipnoans, have a history spanning over 400 million years and are the closest living sister taxon to the tetrapods. Most Devonian lungfish had heavily ossified endoskeletons, whereas most Mesozoic and Cenozoic lungfish had largely cartilaginous endoskeletons and are usually known only from isolated tooth plates or disarticulated bone fragments. There is thus a substantial temporal and evolutionary gap in our understanding of lungfish endoskeletal morphology, between the diverse and highly variable Devonian forms on the one hand and the three extant genera on the other. Here we present a virtual cranial endocast of Rhinodipterus kimberleyensis, from the Late Devonian Gogo Formation of Australia, one of the most derived fossil dipnoans with a well-ossified braincase. This endocast, generated from a Computed Microtomography (µCT) scan of the skull, is the first virtual endocast of any lungfish published, and only the third fossil dipnoan endocast to be illustrated in its entirety. Key features include long olfactory canals, a telencephalic cavity with a moderate degree of ventral expansion, large suparaotic cavities, and moderately enlarged utricular recesses. It has numerous similarities to the endocasts of Chirodipterus wildungensis and Griphognathus whitei, and to a lesser degree to ''Chirodipterus'' australis and Dipnorhynchus sussmilchi. Among extant lungfish, it consistently resembles Neoceratodus more closely than Lepidosiren and Protopterus. Several trends in the evolution of the brains and labyrinth regions in dipnoans, such as the expansions of the utricular recess and telencephalic regions over time, are identified and discussed.     

Eine blütenmorphologische Analyse derLagoecieae (Apiaceae)

An analysis of the morphology, anatomy and ontogeny of the flowers, particularly of the gynoecium ofLagoecieae is presented. 1. The gynoecial model of angiosperms can be applied to all three generaArctopus, Lagoecia andPetagnia. 2. In the case ofArctopus an additional Apikalseptum is developed. 3. In the synascidiate region of the gynoecium the adaxial carpel is reduced inArctopus andPetagnia, the abaxial inLagoecia. 4. The reduced carpel produces either one mature ovule inArctopus, a rudimentary ovule inPetagnia, or none inLagoecia. 5.Petagnia andLagoecia have a completely pseudomonomerous gynoecium. 6.Arctopus displays many flower characteristics which lack in theSaniculoideae but occur in theHydrocotyloideae. 7. ForPetagnia andLagoecia an independent phylogenetic development within theSaniculoideae is assumed.

Herrn Univ.-Prof. Dr.Walter Leinfellner zum 70. Geburtstag gewidmet.     

CHARACTER DIAGNOSIS, FOSSILS AND THE ORIGIN OF TETRAPODS

I. The traditional view of the origin of tetrapod vertebrates is that they are descendants of fossil osteolepiform fish, of which Eusthenopteron is best known. In recent years both that conclusion and the methodology by which it has been reached have been challenged by practitioners of cladistic analysis. Particularly a recent review by Rosen et al. (1981) claims that Dipnoi (lungfish) are the sister-group of the Tetrapoda, that Osteolepiformes is a non-taxon and that Eusthenopteron is more distant from tetrapods than are Dipnoi, coelacanths and probably the fossil Porolepiformes. We attempt to refute all these concludions by use of the same cladistic technique. 2. We accept that all the above-mentioned groups, together with some less well-known taxa, can be united as Sarcopterygii by means of shared derived (apomorph) characters. We also agree that Porolepiformes and Actinistia (coelacanths) can be characterized as valid taxa. The primitive and enigmatic fossil fish Powichthys is accepted as representing the plesiomorph sister-group of true porolepiforms. 3. Only two apomorph features, the course of the jaw adductor muscles and the position of incurrent and excurrent nostrils, appear to unite all the fish, living and fossil, currently regarded as Dipnoi. The characteristic tooth plates and the presence of petrodentine both exclude important primitive fossil forms. 4. Contrary to the opinion of Rosen et al., Osteolepiformes can be characterized — by the arrangement of bones forming the cheek plate, the presence of basal scutes to the fins and by the unjointed radials of the median fins. However, if these are true autapomorphies they exclude any osteolepiform from direct tetrapod ancestry. 5. Tetrapoda is a monophyletic group characterized by ten or more autapomorphies, including the bones of the cheek plate, a stapes and fenestra ovalis, and a series of characters of the appendicular skeleton. 6. Tetrapods have a true choana (internal nostril). We accept that the posterior (excurrent) nostril of Dipnoi is the homologue of the tetrapod choana. However, we assert that the posterior nostril of all bony fish is the homologue of the choana. This assertion would be refuted if any fish showed separate posterior nostril and choana. We reject the claim that this ‘three nostril condition’ occurred in porolepiforms and osteolepiforms. The evidence for a choana in porolepiforms is inadequate. Osteolepiforms had a true choana, characterized as in tetrapods by its relationship to the bones of the palate, but no third nostril. Dipnoans are not choanate. 7. Following cladistic practice, the relationship of the extant taxa is established first. Dipnoi are thus shown to be the living sister-group of tetrapods, but only on ‘soft anatomy’ characters unavailable in fossils. Coelacanths are the living sister-group of the taxon so formed. 8. The relationship of the fossil taxa to the extant sarcopterygians is then considered. The synapomorphy scheme proposed by Rosen et al. is discussed at length. Virtually all the characters they use to exclude close relationship of Eusthenopteron (and hence all osteolepiforms) to tetrapods, in favour of coelacanths and dipnoans, are invalid. 9. A series of synapomorphies uniting osteolepiforms and tetrapods is proposed, including a true choana (hence the taxon Choanata), the histology of the teeth, and a number of characters of the humerus. The recently discovered fossil Youngolepis, which lacks a choana, represents the sister-group of the Choanata, and is not uniquely close to Powichthys. The latter, as a porolepiform (s.l.) is a member of the sister-group to Choanata plus Youngolepis. 10. Our cladistic analysis suggests that all the extinct taxa considered are more closely related to tetrapods than are the Dipnoi. Moreover fossil evidence suggests that Dipnoi, considered as an extant taxon, may not even be the living sister-group of Tetrapoda. Early fossil dipnoans appear to have been marine fish without specific adaptations for air breathing. If so the apparent synapomorphies of Dipnoi and Tetrapoda may be homoplastic — the insistence on grouping extant taxa first would then have yielded an invalid inference.     

The elasmobranch spiracular organ

Summary The spiracular organ is a lateral line derived receptor associated with the first gill cleft (spiracle). Its functional morphology was studied in the little skate,Raja erinacea, and a shark, the smooth dogfish,Mustelus canis, with light and electron microscopy. The spiracular organ is a tube (skate) or pouch (shark) with a single pore opening into the spiracle. The lumen is lined with patches of sensory hair cells, and filled with a gelatinous cupula. In the little skate, hair cells form synapses with afferents but apparently not with efferent fibers. In both species, the spiracular organs are deformed by flexion of the hyomandibular cartilage at its articulation with the cranium. The hyomandibula is a suspensory element of the jaws; hyomandibular flexion results in jaw protrusion. The little skate spiracular organ is anchored at one end to the cranium and at the other to the hyomandibula so that it is stretched or relaxed during hyomandibular extension and flexion, respectively. InMustelus, the effects of hyomandibular flexion on the spiracular organ are mediated indirectly by the superior post-spiracular ligament which inserts on the distal end of the hyomandibula. Deformation of the dogfish shark cupula during hyomandibular movement was observed. In the little skate, as revealed by transmission electron microscopy, there is a measurable deflection of the hair cell ciliary bundles from spiracular organs fixed with the hyomandibula in the flexed relative to the extended positions. In both species, hyomandibula flexion should result in hair cell depolarization, and sensory afferent excitation, based on the direction of the observed (skate) or expected (shark) deflection of hair cell cilia.     

A new assemblage of Cenozoic lungfishes (Dipnoi: Lepidosirenidae) from the late Oligocene Nsungwe Formation,Rukwa Rift Basin,southwestern Tanzania

Lungfish (Dipnoi) date back to the Devonian, and some fossil taxa as well as extant African lungfishes are known for their ability to aestivate, tolerating low-oxygen environments associated with seasonal drying. Extant lungfishes are separated into two families: Lepidosirenidae (Protopterus in Africa and Lepidosiren in South America) and Neoceratodontidae (Neocerotadus in Australia). African lungfishes were more geographically and phylogenetically diverse on the continent in the past than they are today, with only 5% of extinct taxa recorded from the sub-Saharan fossil record. Given the sparse record of Lepidosirenidae fossils from continental Africa, any new materials are important for understanding diversification of the clade. Here we describe new lungfish fossils cautiously referable to Protopterus annectens and Protopterus aethiopicus, which are strongly supported sister taxa based on the molecular phylogeny. Specimens were collected from the late Oligocene Nsungwe Formation in the Rukwa Rift Basin (RRB) of southwestern Tanzania. The late Oligocene Nsungwe Formation represents a sequence of continental rift-fill deposits of the Songwe sub-basin of the RRB and is subdivided into the lower Utengule and upper Songwe members. Recovery of such material from the Paleogene of Africa below the equator addresses a sizable gap in the lungfish fossil record. It also expands the Nsungwe Formation fauna that includes invertebrates, alestid fishes, ptychadenid anurans, snakes, and several clades of mammals, deepening paleoecological insights into the late Oligocene record of the continental African interior. At present, P. aethiopicus and P. dolloi have an extensive modern eastern African distribution associated with the rift lakes and a region where extant members of P. annectens are not presently known. Fossil specimens described herein document presence of the clade during Paleogene volcanic activity in the western branch of the Eastern African Rift System.     

Ontogeny of the osteocranium in the African catfish,Clarias gariepinus Burchell (1822) (Siluriformes: Clariidae): Ossification sequence as a response to functional demands

The ontogeny of the bony skull of the African catfish, Clarias gariepinus, is studied from initial ossification until a complete skull is formed. The ossification sequence in C. gariepinus seems to be related to the functional demands that arise in a developing larva. Early ossification of the opercular bone coincides with the initiation of opercular skin movements. Early ossifications involve several dentulous bones, formed shortly before the transition phase from endogenous to exogenous feeding. The enlarging branchiostegal membrane becomes supported by the gradual adding of branchiostegal rays. Parasphenoid ossification may be related to protection of the brain during prey transport, whereas the several hyoid bones, including the parurohyal, are formed in relation to the increasing loads exerted onto the tendons of the sternohyoideus and consequently onto the hyoid bar. Overall skull reinforcement occurs almost simultaneously, with a whole set of perichondral bones arising especially at places of high mechanical load. The suspensorium becomes protected against dislocation in an anteroposterior direction through a ligamentous connection, which even becomes partially ossified, forming the sesamoid entopterygoid. Later, the cranial lateral-line system becomes enclosed by a set of gutters, which close, frequently becoming plate-like later in ontogeny. The brain also becomes covered dorsally. Additional dentition (prevomeral tooth plates) formation seems to coincide with formation of the opercular four-bar system, as well as with the time the digestive system becomes completely functional. Eventually, unossified regions between the bones become closed off, fortifying and completely covering the skull. J. Morphol. 235:183–237, 1998. © 1998 Wiley-Liss, Inc.     

New crested specimens of the Late Cretaceous pterosaurNyctosaurus

Two recently collected specimens of the Late Cretaceous pterosaurNyctosaurus differ from all previously known specimens in the possession of a large branching cranial crest. The crest extends upward and backward from the posterior skull roof and is nearly three times the length of the skull proper. Despite the large crest, the specimens do not differ significantly in morphology from previously known specimens ofNyctosaurus, and do not seem to represent a new species ofNyctosaurus. The specimens suggest that the cranial crest was developed late in ontogeny, which is consistent with the interpretation of pterosaur cranial crests as intraspecific display structures.      

Sex determination in<Emphasis Type="Italic"> Drosophila melanogaster</Emphasis> and<Emphasis Type="Italic"> Musca domestica</Emphasis> converges at the level of the terminal regulator<Emphasis Type="Italic"> doublesex</Emphasis>

Sex-determining cascades are supposed to have evolved in a retrograde manner from bottom to top. Wilkins 1995 hypothesis finds support from our comparative studies in Drosophila melanogaster and Musca domestica, two dipteran species that separated some 120 million years ago. The sex-determining cascades in these flies differ at the level of the primary sex-determining signal and their targets, Sxl in Drosophila and F in Musca. Here we present evidence that they converge at the level of the terminal regulator, doublesex (dsx), which conveys the selected sexual fate to the differentiation genes. The dsx homologue in Musca, Md-dsx, encodes male-specific (MdDSX^M) and female-specific (MdDSX^F) protein variants which correspond in structure to those in Drosophila. Sex-specific regulation of Md-dsx is controlled by the switch gene F via a splicing mechanism that is similar but in some relevant aspects different from that in Drosophila. MdDSX^F expression can activate the vitellogenin genes in Drosophila and Musca males, and MdDSX^M expression in Drosophila females can cause male-like pigmentation of posterior tergites, suggesting that these Musca dsx variants are conserved not only in structure but also in function. Furthermore, downregulation of Md-dsx activity in Musca by injecting dsRNA into embryos leads to intersexual differentiation of the gonads. These results strongly support a role of Md-dsx as the final regulatory gene in the sex-determining hierarchy of the housefly.Edited by D. Tautz     

Comparative analysis of the hyomandibula during respiration in anabantoid teleost fishes:Macropodus opercularis in relation toCtenopoma acutirostre andAnabas testudineus

Summary The hyomandibula is an important element of the head and has been influenced in its structural features by different functions. It is roughly T-shaped with vertical and horizontal ridges. In fish, such asMacropodus opercularis, the deep curve at the antero-dorsal end of this ridge may be correlated with the concentrated force applied by the adductor mandibulae muscles. InMacropodus opercularis, the hyomandibula is shorter and broader than that ofAnabas testudineus andCtenopoma acutirostre. In the latter two genera, almost the entire anterior surface of the vertical ridge is uniformly curved, which may be explained by the distributive force applied by the adductor muscles perpendicularly. InMacropodus, the hyomandibulo-interhyal articulation is not straight along the axis of the interhyal as inCtenopoma, but the interhyal makes an angle of 45 to the hyomandibula. This difference might be functional as well as due to the oblique orientation of the hyomandibula. InCtenopoma, the articulating facet of the symplectic is located slightly below the interhyal articulating facet. This might be caused by the location of the hyomandibulo-interhyal articulation. The hyomandibulo-interhyal articulation also helps in the depression of the lower jaw when the latter is depressed by the hyoid bar. Thus, a structural analysis of the hyomandibula and its relationships with functions depict the interrelation between form and function.     

Ein primitiver acanthodier (pisces) aus dem unterdevon lettlands

Latviacanthus ventspilsensis n.gen., n.sp. is described from a drilling core at Ventspils, Latvia, U.S.S.R. It is placed nearEuthacanthus, Climatiidae, chiefly on the basis of similarities in the gill region (1 hyoid and 3 accessoric gill covers). Main features ofLatviacanthus are: palatoquadrate and Meckel’s cartilage ossified as a single element each, multiple-cuspid teeth not fused to the jaws, slender pectoral spine, weakly developed dermal shoulder-girdle.     

Establishment,counts, and identification of the fibrolytic microflora in the digestive tract of rabbit. Influence of feed cellulose content

Dam-mediated adenine methylation at GATC sites can interfere with gene expression. By use oflacZ fusion technology, the efficiency oftrpR andtrpS promoters (which contain a GATC site) and oftrp (the target of TrpR repressor) was analyzed indam ⁺ anddam ^– backgrounds. In exponentially growing cells, thedam mutation leads to an increased activity oftrpR promoter but does not affecttrpS ortrp promoters. The Dam-mediated induction oftrpR was, however, found to be repressed bytrpR-mediated autoregulation. In contrast,trp-lacZ directed-galactosidase activity was increased at least sixfold indam ^– cells in late logarithmic growth phase. Indam ⁺ cells, expression oftrp-lacZ was similarly late-growth-phase induced, albeit to a reduced extent. Hence, we propose that enhancement of growth phase-dependent gene induction constitutes a previously unidentified trait ofdam mutation. This finding is discussed in the context of the pleiotropic phenotype ofdam mutation.     

Karyosystematics and evolution of AustralianAnnonaceae as compared withEupomatiaceae,Himantandraceae, andAustrobaileyaceae

Chromosome counts are presented for 12 genera and 20 species of AustralianAnnonaceae (all diploid with 2n = 16 or 18; Table 1) and two species ofEupomatiaceae (2n = 20, partly from Papua New Guinea). Detailed studies on interphase nuclear structure, condensing behaviour of chromosomes, and fluorochrome and Giemsa C-banding patterns also includeHimantandraceae (Galbulimima) andAustrobaileyaceae. — Eupomatiaceae completely correspond withAnnonaceae karyologically, their base number 2n = 20 is interpreted to have evolved from 2n = 18 by ascending dysploidy from common ancestors.Eupomatia laurina andE. benettii differ in DNA and constitutive heterochromatin (hc) quantity; their evolution from high to low DNA content probably corresponds to general progressions inMagnoliidae. Austrobaileya has nuclei of the presumably primitive Tetrameranthus type which is closely related to that ofGalbulimima and several other primitive taxa inMagnoliidae. Karyomorphology and other characters support the maintainance of two main branches within theMagnoliidae, Laurales andMagnoliales, withAustrobaileya probably intermediate; theWinteraceae appear more remote.—InAnnonaceae the reestablishment ofAncana is underlined by its chromosome number (2n = 18) the unexpected and specialized disulcate pollen, and various morphological characters which point to a close alliance with the Australian endemic generaFitzalania andHaplostichanthus (also disulcate) and the American genus pairSapranthus/Desmopsis; they are united in the provisionalSapranthus tribe, with a more distant position toFissistigma s. str. (2n = 16). AustralianAnnonaceae exhibit a high generic and a low species diversity; they can be considered as an ± old and partly impoverished outpost of the family with phytogeographical relationships to Asia, Africa and America.—On the base of field observations three main types of floral development inAnnonaceae are proposed, the most elaborated one found in the fly pollinated genusPseuduvaria. The growth form change from shrubs to lianas during the ontogeny ofDesmos andMelodorum, the vegetative propagation of anAncana species and the ecological and evolutionary patterns of the taxa investigated are discussed.