Dependence of the Stomatal Index on Environmental Factors during Stomatal Differentiation in Leaves of Vigna sinensis L.: II. EFFECT OF DIFFERENT LIGHT QUALITY

Using appropriate coloured lights, we show that phytochromeis involved in stomatal differentiation. This photoperceptionis located within the whole shoot. This action is also shownfor in vitro leaves. The nature of the morphogenetic informationis discussed. Key words: Stomatal differentiation, Phytochromy, Vigna sinensis L.     

REVISION OF THE TYPE MATERIAL AND NOMENCLATURE OF MASTODONSAURUS GIGANTEUS (JAEGER) (TEMNOSPONDYLI) FROM THE MIDDLE TRIASSIC OF GERMANY

Abstract: The type material of Mastodonsaurus is revised and its complicated taxonomic history resolved. The genus was erected by Jaeger in 1828 without a species name, which was added subsequently by Holl (1829) who named the type species Mastodonsaurus jaegeri. The large tooth on which Jaeger based his Mastodonsaurus is chosen herein as lectotype of the type species. A smaller second individual, represented by a piece of an occiput, was also named by Jaeger in 1828 as Salamandroides giganteus and, owing to the find of a complete skull, was recognized in 1833 by the same author as belonging to the same species as the Mastodonsaurus. Therefore, Mastodonsaurus giganteus (Jaeger, 1828) is a senior subjective synonym of the type species M. jaegeri Holl, 1829. The precedence of the two generic names was chosen in 1834 by the first reviser, von Alberti, in favour of Salamandroides, but all later authors, including von Alberti himself, followed Jaeger, who decided in 1837 to retain the name Mastodonsaurus. The established usage of Mastodonsaurus is preserved formally herein (nomen protectum). The names Batrachosaurus Fitzinger, 1837, and Labyrinthodon Owen, 1841 are unjustified replacement names of Mastodonsaurus. The names M. jaegeri von Meyer, 1832, S. jaegeri von Alberti, 1834 and M. salamandroides Jaeger, 1837 are junior homonyms and synonyms of M. jaegeri Holl, 1829, and M. giganteus (Jaeger, 1828), respectively. A recent attempt to replace the universally used Capitosauroidea Watson, 1919 by the unused and newly elevated Mastodonsauroidea Lydekker, 1885 is rejected. Two older synonyms of Mastodonsauridae Lydekker, 1885 (nomen protectum) are rejected as unavailable (Labyrinthodontidae von Meyer, 1842 ) and nomen oblitum (Batrachosauridae Fitzinger, 1843), respectively. The holotype of Mastodonsaurus giganteus is reinstated and valid on the basis of three diagnostic features present: the tripartite posterior rim of the parasphenoid, a laterally pushed suture between the parasphenoid and basipterygoid, and a wide slit‐like eustachian tube opening. Mastodonsaurus is known from specimens representing a continuous growth series, now also encompassing the lectotype of Mastodonsaurus jaegeri, which until rather recently stood isolated from other specimens as the largest find by far.     

A chroniosuchid from the Triassic of Kyrgyzstan and analysis of chroniosuchian relationships

A nearly complete skull and associated osteoderms from the Middle/Upper Triassic Madygen Formation of Kyrgyzstan are referred to a new chroniosuchid genus and species. The new taxon is characterized by a parabolic skull outline, pustular ornamentation, tabular‐squamosal contact, marked postparietal embayments, and the lack of an antorbital fontanelle. The palate is only preserved in part, showing broad palatines and ectopterygoids. Presence of a preorbital fenestra and characteristic osteoderm morphology are synapomorphies shared with all other chroniosuchids. According to the phylogenetic analysis performed, the new chroniosuchid nests with Chroniosaurus, with which it shares the wide, transversely extended osteoderms and pustular ornamentation. The chroniosuchians are robustly supported as a natural group, but their position within the reptiliomorph (stem‐amniote) clade is not adequately understood. Whereas the parasphenoid is similar to that of anthracosaurs, most other characters support a higher nesting of chroniosuchians within the stem‐amniotes. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 515–530.     

A new stereospondyl from the German Middle Triassic, and the origin of the Metoposauridae

Recent finds of well-preserved temnospondyl skeletons from the Lower Keuper (Ladinian, Middle Triassic) in southern Germany are assigned to a new genus and species, Callistomordax kugleri . This taxon is characterized by the following autapomorphies: (1) wide unpaired frontal; (2) vomerine fangs greatly enlarged to occupy entire width of element; (3) intercentra elongated and massive, anterior face being convex; (4) humerus semilunar with enlarged deltopectoral crest; (5) cleithrum strongly curved and bow-shaped; (6) trunk extremely elongated to reach three times the length of the skull. Callistomordax shares with the Metoposauridae the pattern of dermal ornamentation, the proportion of both posterior skull table and snout, the position of the lacrimal, the morphology of the basicranial region, and the structure of the clavicle and interclavicle. Phylogenetic analysis suggests Callistomordax to be the sister taxon of the Metoposauridae, nested within a grade formed by various trematosaurian taxa. In this assemblage, Lyrocephaliscus and a clade formed by Almasaurus , Rileymillerus , Callistomordax , and the Metoposauridae are sister taxa. In all variants of the cladistic analysis, Callistomordax and the Metoposauridae form immediate sister groups. According to the present findings, neither plagiosaurids nor brachyopoids and rhytidosteids are closely related to this 'trematosaurian' monophylum, although these taxa share a range of homoplasies.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 79–113.     

Osteology and relationships of the temnospondyl genus Sclerocephalus

The temnospondyl Sclerocephalus from the Permo‐Carboniferous of Germany is one of the most completely preserved and most abundant Palaeozoic tetrapods. Here, we review the complete osteology of the genus, based on a range of fully grown specimens housed in public collections. Among the four valid species, Sclerocephalus haeuseri and Sclerocephalus nobilis reached an adult size of well beyond 1 m in length, and had robust postcranial skeletons. In the skull, the exoccipital and sphenethmoid bones were ossified, completing the well‐known ossification sequence in S. haeuseri. Large adults had an elongate trunk and a laterally compressed tail, and some individuals also retained lateral line sulci: features that taken together suggest an aquatic life. The coracoid, pubis, carpals, tarsals, and the bony tail are fully ossified in the largest specimens. The genus Sclerocephalus forms a weakly supported clade nesting firmly at the base of the Stereospondylomorpha, and the close resemblance between Sclerocephalus, Onchiodon, and Eryops is found to be partially based on shared derived states, but is mostly based on symplesiomorphies. Cladistic analysis of 54 characters and 18 taxa finds more support for the Eryopoidea hypothesis (Eryopidae + Stereospondylomorpha) than for the Euskelia hypothesis (Eryopidae + Zatracheidae + Dissorophoidea). This indicates that the large temnospondyls of the Permian and Mesozoic probably formed a natural group, and that the terrestrial adaptations of Eryops and the dissorophoids probably evolved by convergence.     

The plagiosaurid temnospondyl Plagiosuchus pustuliferus (Amphibia: Temnospondyli) from the Middle Triassic of Germany: anatomy and functional morphology of the skull

The cranial anatomy of the plagiosaurid temnospondyl Plagiosuchus pustuliferus, from the Middle Triassic of Germany, is described in detail on the basis of a newly discovered skull and mandibular material. The highly derived skull is characterized by huge orbitotemporal fenestrae, a reduction of the circumorbital bones – the prefrontal, postfrontal and (probably) postorbital are lost – and the expansion of the jugal to occupy most of the lateral skull margin. Ventrally the extremely long subtemporal vacuities correlate with the elongate adductor fossa of the mandible. The dentition is feebly developed on both skull and mandible. Ossified ?ceratobranchials and ‘branchial denticles’ indicate the presence of open gills clefts in life. The remarkably divergent cranial morphology of P. pustuliferus highlights the extraordinary cranial diversity within the Plagiosauridae, probably unsurpassed within the Temnospondyli. Specific structural aspects of the skull – including an extremely short marginal tooth row, feeble dentition and an elongated chamber for adductor musculature – together with evidence for a hyobranchial skeleton, suggests that P. pustuliferus utilized directed suction feeding for prey capture. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 348–373.     

Cranial morphology of the plagiosaurid Gerrothorax pulcherrimus as an extreme example of evolutionary stasis

Schoch, R.R. & Witzmann, F. 2011: Cranial morphology of the plagiosaurid Gerrothorax pulcherrimus as an extreme example of evolutionary stasis. Lethaia, Vol. 45, pp. 371–385. The plagiosaurid Gerrothorax pulcherrimus from the Triassic of Greenland and Germany is represented by skulls ranging from 4 to 12 cm in length and sheds light on ontogeny, individual variation, and variation in time and space. Ontogeny was remarkably stable in G. pulcherrimus, with the smallest known specimens resembling the adults closely in most features. A true ontogenetic change is evident in the ornament of dermal bones, in that the smallest specimens have ridges whereas in the successively larger ones, pustules spread over increasingly larger areas. The skull becomes proportionally longer, and the adductor chambers relatively narrower. The positive allometry of both the orbits and the interpterygoid vacuities suggests that the eye supporting musculature – rather than the jaw adductors – increased proportionally during growth. Individual, not age‐related variation in the dermal skull roof affects partial fusion of parietals, presence and extent of the interfrontoparietal, and the morphological pattern of the posterior skull table. The ventral surface of the basal plate of the parasphenoid ranges from smooth over poorly to heavily ornamented or dentigerous. Considering the impressive longevity of more than 35 Myr, the morphological changes of G. pulcherrimus are minor. Our ecological interpretation for G. pulcherrimus is that it relied on the permanent presence of water, but was flexible with respect to the size and nature of the water body as well as to changes in salinity. The unparalleled extent of evolutionary stasis may therefore be based on the ecological flexibility of this morphologically so tightly constrained temnospondyl. □Ecological flexibility, ontogeny,Temnospondyli, Triassic, variation.     

X-ray Microanalysis of the Mineral Contents of Some Protozoa

With the aid of energy-dispersive X-ray microanalysis, several protozoa were tested for content of cations within inorganic minerals. The skeleton of acantharia consists mainly of Sr with small quantities of Ca and Ba. Two Loxodes species contain nothing but Ba, while in some Remanella species Sr with small quantities of Ba were present. In one Geleia species, Ca with small quantities of Sr was found; in two Trachelocerca species from Sylt (Germany), Ba is there in addition. Another Trachelocerca species from northern Italy lacked Ba, but did possess Mn. In Prorodon only Ca was found.     

Braincase,palatoquadrate and ear region of the plagiosaurid Gerrothorax pulcherrimus from the Middle Triassic of Germany

Abstract: The complete neurocranium plus palatoquadrate of the plagiosaurid temnospondyl Gerrothorax pulcherrimus from the Middle Triassic of Germany is described for the first time, based on outer morphological observations and micro‐CT scanning. The exoccipitals are strong elements with paroccipital processes and well‐separated occipital condyles. Anterolaterally, the exoccipitals contact the otics, which are mediolaterally elongated and have massive lateral walls. The otics contact the basisphenoid, which shows well‐developed sellar processes. Anteriorly, the basisphenoid is continuous with the sphenethmoid region. In its posterior portion, the sphenethmoid gives rise to robust, laterally directed laterosphenoid walls, a unique morphology among basal tetrapods. The palatoquadrate is extensively ossified. The quadrate portion overlaps the descending lamina of squamosal and ascending lamina of pterygoid anteriorly, almost contacting the epipterygoid laterally. The epipterygoid is a complex element and may be co‐ossified with otics and laterosphenoid walls. It has a broad, sheet‐like footplate and a horizontally aligned ascending process that contacts the laterosphenoid walls. The degree of ossification of the epipterygoid, however, is subject to individual variation obviously independent from ontogenetic changes. The stapes of Gerrothorax is a large, blade‐like element that differs conspicuously from the plesiomorphic temnospondyl condition. It has a prominent anterolateral projection which has not been observed in other basal tetrapods. Morphology of neurocranium and palatoquadratum of Gerrothorax most closely resembles that of the Russian plagiosaurid Plagiosternum danilovi, although the elements are less ossified in the latter. The extensive endocranial ossification of Gerrothorax is consistent with the general high degree of ossification in the exo‐ and endoskeleton of this temnospondyl and supports the view that a strong endocranial ossification cannot be evaluated as a plesiomorphic character in basal tetrapods.