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Thursday, November 4th, 2021
| Time | Event | ||||||
| 12:33a | [Botany • 2021] Taxonomic Notes on Pavetta L. (Rubiaceae) from Thailand and New Records for Cambodia, Laos and Myanmar
Abstract A taxonomic revision of genus Pavetta in Thailand is presented, 14 species (15 taxa) are listed, namely P. aspera Craib, P. brevituba Craib, P. fruticosa Craib, P. graciliflora Wall. ex Ridl., P. humilis Hook.f., P. kedahica Bremek., P. napieri (Ridl.) Bremek., P. naucleiflora R.Br. ex G. Don, P. petiolaris Craib, P. salicina (Ridl.) Bremek., P. siamica Bremek., P. sylvatica Blume, P. tomentosa Roxb. ex Sm., P. tomentosa var. glabrescens (Kurz) Craib and P. wallichiana Steud. ex Craib, one of which, P. brevituba is endemic to Thailand. Lectotypes for Pavetta aspera, P. aspera var. breviflos Craib, P. graciliflora var. latifolia Craib, P. indica L. var. polyantha Hook.f., P. laoticensis Bremek., P. naucleiflora R. Br. ex G. Don, P. petiolaris and P. pierrei Bremek. are designated. Pavetta finlaysoniana Wall. ex Bremek. and P. laoticensis Bremek., are reduced to synonymy under P. aspera. Pavetta birmanica Bremek., P. birmanica var. glabrescens Bremek., P. birmanica var. tomentosa Bremek. and P. gamblei Bremek., are reduced to P. fruitcosa and P. pusilliflora Bremek. is reduced to P. petiolaris. Pavetta formosa Bremek. is also reduced to P. wallichiana. One species new to Thailand, Pavetta napieri; one new to Myanmar, P. aspera; one to Cambodia, P. sylvatica and two to Laos, P. fruticosa and P. naucleiflora. A key to the species of Pavetta in Thailand is provided with distribution, ecology and vernacular names. Specimens examined and photographes of some species are also given. Keywords: lectotype, Pavetteae, synonym, taxonomy Pavetta L. (Rubiaceae-Pavetteae) is one of the large genera of the Rubiaceae, comprising ca 400 species with a pantropical distribution, which occur in Africa, through India, SE Asia and Australia. (Mabberley, 2008). The name Pavettais derived from ‘pawatta’ a Singhalese and Malayalee plant name (Wong, 1989). Most species are widespread along the margins of deciduous, mixed deciduous, dry evergreen and evergreen forests. The dark bacterial nodules on the leaves are the most distinguished characters of the genus. The plants in the Rubiaceae are familiar through cultivated ornamentals as Gardenia J.Ellis, Ixora L., Mussaenda Burm. ex L., Pentas Benth. and Tarenna Gaertn. but not Pavetta. ...
Pranom Chantaranothai. 2021. Taxonomic Notes on Pavetta L. (Rubiaceae) from Thailand and New Records for Cambodia, Laos and Myanmar. Tropical Natural History. 21(1); 146-166. Pavetta finlaysoniana Wall. ex Bremek. and P. laoticensis Bremek., are reduced to synonymy under P. aspera. Pavetta birmanica Bremek., P. birmanica var. glabrescens Bremek., P. birmanica var. tomentosa Bremek. and P. gamblei Bremek., are reduced to P. fruitcosa P. pusilliflora Bremek. is reduced to P. petiolaris. Pavetta formosa Bremek. is reduced to P. wallichiana. One species new to Thailand, Pavetta napieri; one new to Myanmar, P. aspera; one to Cambodia, P. sylvatica two to Laos, P. fruticosa and P. naucleiflora. | ||||||
| 1:02p | [Paleontology • 2021] Issi saaneq • A New Sauropodomorph Dinosaur (Saurischia: Plateosauridae) from the Late Triassic (Norian) of Jameson Land, Central East Greenland
Abstract The Late Triassic (Norian) outcrops of the Malmros Klint Formation, Jameson Land (Greenland) have yielded numerous specimens of non-sauropod sauropodomorphs. Relevant fossils were briefly reported in 1994 and were assigned to Plateosaurus trossingensis. However, continuous new findings of early non-sauropod sauropodomorphs around the globe facilitate comparisons and allow us to now revise this material. Here, the non-sauropod sauropodomorph Issi saaneq gen. et sp. nov. is described based on two almost complete and articulated skulls. The two skulls represent a middle-stage juvenile and a late-stage juvenile or subadult. Issi saaneq differs from all other sauropodomorphs by several unique traits: (1) a small foramen at the medial surface of the premaxilla; (2) an anteroposteriorly elongated dorsoposterior process of the squamosal; (3) a relatively high quadrate relative to rostrum height; (4) a well-developed posterodorsal process of the articular. These features cannot be explained by taphonomy, ontogeny, or intraspecific variation. Issi saaneq shows affinities to Brazilian plateosaurids and the European Plateosaurus, being recovered as the sister clade of the latter in our phylogenetic analysis. It is the northernmost record of a Late Triassic sauropodomorph, and a new dinosaur species erected for Greenland. Issi saaneq broadens our knowledge about the evolution of plateosaurid sauropodomorphs. Keywords: sauropodomorph; Triassic; plateosaurid; dinosaur; Greenland  Systematic Palaeontology Dinosauria Saurischia Sauropodomorpha Plateosauridae Issi saaneq gen. et sp. nov. Etymology: From Kalaallisut, “issi” meaning cold and “saaneq” meaning bone. Pronounced ‘is‐ y sa‐ah‐neq’. In reference to the conditions in which the fossils were recovered. We have selected a name in Inuit language to honor the local culture. Horizon and Age: NHMD 164741 and NHMD 164758 were collected at Malmros Klint Formation, Flem‐ ing Fjord Group, of mid‐Norian stage of the Late Triassic Diagnosis: Issi saaneq can be distinguished from other basal sauropodomorphs on the basis of a unique trait combination comprising six phylogenetic synapomorphies (i) and four cra‐ nial autapomorphies (ii). (i) weakly developed narial fossa (character 10, state 0); small subnarial foramen (12, 1); anterior margin of the external naris anterior to the mid‐length of the premaxilla (17, 0); anteroposterior length of the antorbital fossa less than that of the orbit (28, 1); antorbital fossa ending before the ventral process of the lacrimal (41, 1); strongly curved jugal process of the ectopterygoid (86, 1). (ii) the presence of a small fora‐ men at the medial surface of the premaxilla at the base of the lateral process of the pre‐ maxilla; an anteroposteriorly elongated dorsoposterior process of the squamosal; a quad‐ rate relatively tall in comparison to the rostrum height; a well‐developed posterodorsal process of the articular, square‐shaped in lateral view. Issi saaneq possesses features thought to be autapomorphic to other plateosaurids, i.e., five teeth in the premaxilla (as in Plateosaurus), a promaxillary fenestra (as in the Brazilian plateosaurids Macrocollum itaquii and Unaysaurus tolentinoi), a lateral sheet of bone in the lacrimal covering the posterodorsal corner of the antorbital fenestra (as in Plateosaurus trossingensis), and a secondary fossa ventral to the Meckelian groove (as in U. tolentinoi).    Conclusions: Two skulls of the new basal sauropodomorph (plateosaurid) dinosaur taxon Issi saaneq gen. nov. sp. nov. from the Late Triassic (Norian) of Jameson Land, central East Greenland are described based on data retrieved with μCT‐scan image segmentation and photogrammetry. Both specimens, NHMD 164741 and NHMD 164758, were recovered from the uppermost Malmros Klint Formation in Greenland, and due to strong morpho‐ logical similarities and no robust distinguishing features between them, are here regarded as a single taxon. The smaller NHMD 164758 represents an early‐stage juvenile, due to the reduced gap between the first premaxillary teeth and the anterior margin of the premaxilla, large orbit, low number of teeth positions in the dentary and an anteriorly deflected basipterygoid process of the basisphenoid. The specimen NHMD 164741 represents either a late‐stage juvenile or a young adult, due to a proportionally shorter orbit than NHMD 164758 and having a possible maximum of 20 dentary teeth positions. Issi saaneq differs from all other basal sauropodomorphs in four observed autapomorphies: (1) the presence of a small foramen at the medial surface of the premaxilla at the base of the lateral process of the premaxilla; (2) an anteroposteriorly elongated dorsoposterior process of the squamosal; (3) a quadrate relatively tall in comparison to the rostrum height; and (4) Six ambiguous synapomorphies position Issi saaneq as the sister clade to Plateosaurus (Pl. trossingensis and Pl. gracilis). The Brazilian sauropodomorphs were recovered at the base of Plateosauridae and forming the sister clade to the clade containing Issi saaneq and Plateosaurus. Issi saaneq possesses a set of features thought to be exclusive of the Brazilian plateosaurids. Issi saaneq is the first sauropodomorph to reach the Northernmost parts of Laurasia and increases our understanding of the diversity of plateosaurids Victor Beccari, Octávio Mateus, Oliver Wings, Jesper Milàn and Lars B. Clemmensen. 2021. Issi saaneq gen. et sp. nov.—A New Sauropodomorph Dinosaur from the Late Triassic (Norian) of Jameson Land, Central East Greenland. Diversity. 13(11), 561. DOI: 10.3390/d13110561 | ||||||
| 3:01p | [Mammalogy • 2021] Mammalian Face as An Evolutionary Novelty
Significance: The anatomical framework of the jaw has traditionally been thought to be highly conserved among vertebrates. However, here we show that the therian-unique face (muzzle) evolved via a drastic alteration of the common pattern of the tetrapod jaw. Through comparative morphological and developmental analyses, we demonstrated that the therian mammal’s premaxilla (rostral-most upper jawbone) is derived from the maxillary prominence of the mandibular arch. The developmental primordium that produces the premaxilla in nonmammalian tetrapods rarely contributes to the upper jaw in therian mammals but rather forms a motile nose. We propose that these previously unrecognized rearrangements allowed key innovations such as the highly sensitive tactile perception and olfactory function in mammalian evolution. Abstract The anterior end of the mammalian face is characteristically composed of a semimotile nose, not the upper jaw as in other tetrapods. Thus, the therian nose is covered ventrolaterally by the “premaxilla,” and the osteocranium possesses only a single nasal aperture because of the absence of medial bony elements. This stands in contrast to those in other tetrapods in whom the premaxilla covers the rostral terminus of the snout, providing a key to understanding the evolution of the mammalian face. Here, we show that the premaxilla in therian mammals (placentals and marsupials) is not entirely homologous to those in other amniotes; the therian premaxilla is a composite of the septomaxilla and the palatine remnant of the premaxilla of nontherian amniotes (including monotremes). By comparing topographical relationships of craniofacial primordia and nerve supplies in various tetrapod embryos, we found that the therian premaxilla is predominantly of the maxillary prominence origin and associated with mandibular arch. The rostral-most part of the upper jaw in nonmammalian tetrapods corresponds to the motile nose in therian mammals. During development, experimental inhibition of primordial growth demonstrated that the entire mammalian upper jaw mostly originates from the maxillary prominence, unlike other amniotes. Consistently, cell lineage tracing in transgenic mice revealed a mammalian-specific rostral growth of the maxillary prominence. We conclude that the mammalian-specific face, the muzzle, is an evolutionary novelty obtained by overriding ancestral developmental constraints to establish a novel topographical framework in craniofacial mesenchyme. Keywords: evolution, craniofacial, skull, mammals 
Hiroki Higashiyama, Daisuke Koyabu, Tatsuya Hirasawa, Ingmar Werneburg, Shigeru Kuratani, and Hiroki Kurihara. 2021. Mammalian Face as An Evolutionary Novelty. PNAS. 118 (44); e2111876118. DOI: 10.1073/pnas.2111876118 |
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