scholarly journals Extreme miniaturization of a new amniote vertebrate and insights into the evolution of genital size in chameleons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Frank Glaw ◽  
Jörn Köhler ◽  
Oliver Hawlitschek ◽  
Fanomezana M. Ratsoavina ◽  
Andolalao Rakotoarison ◽  
...  

AbstractEvolutionary reduction of adult body size (miniaturization) has profound consequences for organismal biology and is an important subject of evolutionary research. Based on two individuals we describe a new, extremely miniaturized chameleon, which may be the world’s smallest reptile species. The male holotype of Brookesia nana sp. nov. has a snout–vent length of 13.5 mm (total length 21.6 mm) and has large, apparently fully developed hemipenes, making it apparently the smallest mature male amniote ever recorded. The female paratype measures 19.2 mm snout–vent length (total length 28.9 mm) and a micro-CT scan revealed developing eggs in the body cavity, likewise indicating sexual maturity. The new chameleon is only known from a degraded montane rainforest in northern Madagascar and might be threatened by extinction. Molecular phylogenetic analyses place it as sister to B. karchei, the largest species in the clade of miniaturized Brookesia species, for which we resurrect Evoluticauda Angel, 1942 as subgenus name. The genetic divergence of B. nana sp. nov. is rather strong (9.9‒14.9% to all other Evoluticauda species in the 16S rRNA gene). A comparative study of genital length in Malagasy chameleons revealed a tendency for the smallest chameleons to have the relatively largest hemipenes, which might be a consequence of a reversed sexual size dimorphism with males substantially smaller than females in the smallest species. The miniaturized males may need larger hemipenes to enable a better mechanical fit with female genitals during copulation. Comprehensive studies of female genitalia are needed to test this hypothesis and to better understand the evolution of genitalia in reptiles.

ZooKeys ◽  
2020 ◽  
Vol 943 ◽  
pp. 91-118 ◽  
Author(s):  
Shi-Ze Li ◽  
Jing Liu ◽  
Gang Wei ◽  
Bin Wang

A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described based on molecular phylogenetic analyses, morphological comparisons, and bioacoustics data. Phylogenetic analyses based on the mitochondrial 16S rRNA gene sequences supported the new species as an independent clade nested into the Leptobrachella clade and sister to L. bijie. The new species could be distinguished from its congeners by a combination of the following characters: small body size (SVL 30.8–33.4 mm in seven adult males, and 34.2 mm in one adult female); dorsal skin shagreened, some of the granules forming longitudinal short skin ridges; tympanum distinctly discernible, slightly concave; internasal distance longer than interorbital distance; supra-axillary, femoral, pectoral and ventrolateral glands distinctly visible; absence of webbing and lateral fringes on fingers; toes with rudimentary webbing and shallow lateral fringes, relative finger lengths II < IV < I < III; heels overlapped when thighs are positioned at right angles to the body; and tibia-tarsal articulation reaches the tympanum.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Sesilje Weiss ◽  
David Taggart ◽  
Ian Smith ◽  
Kristofer M. Helgen ◽  
Raphael Eisenhofer

Abstract Background Marsupials are born much earlier than placental mammals, with most crawling from the birth canal to the protective marsupium (pouch) to further their development. However, little is known about the microbiology of the pouch and how it changes throughout a marsupial’s reproductive cycle. Here, using stringent controls, we characterized the microbial composition of multiple body sites from 26 wild Southern Hairy-nosed Wombats (SHNWs), including pouch samples from animals at different reproductive stages. Results Using qPCR of the 16S rRNA gene we detected a microbial community in the SHNW pouch. We observed significant differences in microbial composition and diversity between the body sites tested, as well as between pouch samples from different reproductive stages. The pouches of reproductively active females had drastically lower microbial diversity (mean ASV richness 19 ± 8) compared to reproductively inactive females (mean ASV richness 941 ± 393) and were dominated by gram positive bacteria from the Actinobacteriota phylum (81.7–90.6%), with the dominant families classified as Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, and Dietziaceae. Three of the five most abundant sequences identified in reproductively active pouches had closest matches to microbes previously isolated from tammar wallaby pouches. Conclusions This study represents the first contamination-controlled investigation into the marsupial pouch microbiota, and sets a rigorous framework for future pouch microbiota studies. Our results indicate that SHNW pouches contain communities of microorganisms that are substantially altered by the host reproductive cycle. We recommend further investigation into the roles that pouch microorganisms may play in marsupial reproductive health and joey survival.


Nematology ◽  
2018 ◽  
Vol 20 (7) ◽  
pp. 653-669 ◽  
Author(s):  
Oleg Gorgadze ◽  
Elena Fanelli ◽  
Manana Lortkhipanidze ◽  
Alberto Troccoli ◽  
Medea Burjanadze ◽  
...  

Summary A new species of entomopathogenic nematode, Steinernema borjomiense n. sp., was isolated from the body of the host insect, Oryctes nasicornis (Coleoptera: Scarabaeidae), in Georgia, in the territory of Borjomi-Kharagauli. Morphological characters indicate that the new species is closely related to species of the feltiae-group. The infective juveniles are characterised by the following morphological characters: body length of 879 (777-989) μm, distance between the head and excretory pore = 72 (62-80) μm, pharynx length = 132 (122-142) μm, tail length = 70 (60-80) μm, ratio a = 26.3 (23.0-29.3), H% = 45 (40-51), D% = 54 (47-59), E% = 102 (95-115), and lateral fields consisting of seven ridges (eight incisures) at mid-body. Steinernema borjomiense n. sp. was molecularly characterised by sequencing three ribosomal regions (the ITS, the D2-D3 expansion domains and the 18S rRNA gene) and the mitochondrial COI gene. Phylogenetic analyses revealed that S. borjomiense n. sp. differs from all other known species of Steinernema and is a member of the monticolum-group.


Zootaxa ◽  
2012 ◽  
Vol 3235 (1) ◽  
pp. 1 ◽  
Author(s):  
SHAO YING LIU ◽  
ZHI YU SUN ◽  
YANG LIU ◽  
HAO WANG ◽  
PENG GUO ◽  
...  

During a faunal survey in southern Xizang, we collected 27 specimens of voles that could not be identified as any knownspecies in the Arvicolinae. These specimens shared the following morphological characteristics, not corresponding withany other arvicoline species: the first lower molar possessed five closed triangles, the third upper molar exhibited eitherfour or three inner angles, and the tails of all specimens measured 30% of the body length. Their proximal baculum of theglans was very sturdy and trumpet-shaped, the distal baculum was tongue-like and sturdy, and the lateral bacula were veryshort. Molecular phylogenetic analyses based on nucleotide sequences of the mitochondrial cytochrome b (cyt b) geneclustered these specimens as a distinct lineage within the genus Neodon. According to the morphological and moleculardata, we described them as a new species, Neodon linzhiensis. Our phylogenetic analysis strongly supported that Lasio-podomys fuscus, Phaiomys leucurus, Neodon sikimensis, N. irene and the new species formed a monophyletic group, notincluding N. juldaschi. We suggested that L. fuscus and P. leucurus should be transferred to Neodon and that N. juldaschishould be removed from this genus. Following our new delineation of Neodon, we proposed a redefinition of the morphological diagnostic characters of the genus.


2004 ◽  
Vol 54 (1) ◽  
pp. 175-181 ◽  
Author(s):  
Costantino Vetriani ◽  
Mark D. Speck ◽  
Susan V. Ellor ◽  
Richard A. Lutz ◽  
Valentin Starovoytov

A thermophilic, anaerobic, chemolithoautotrophic bacterium was isolated from the walls of an active deep-sea hydrothermal vent chimney on the East Pacific Rise at 9° 50′ N. Cells of the organism were Gram-negative, motile rods that were about 1·0 μm in length and 0·6 μm in width. Growth occurred between 60 and 80 °C (optimum at 75 °C), 0·5 and 4·5 % (w/v) NaCl (optimum at 2 %) and pH 5 and 7 (optimum at 5·5). Generation time under optimal conditions was 1·57 h. Growth occurred under chemolithoautotrophic conditions in the presence of H2 and CO2, with nitrate or sulfur as the electron acceptor and with concomitant formation of ammonium or hydrogen sulfide, respectively. Thiosulfate, sulfite and oxygen were not used as electron acceptors. Acetate, formate, lactate and yeast extract inhibited growth. No chemoorganoheterotrophic growth was observed on peptone, tryptone or Casamino acids. The genomic DNA G+C content was 54·6 mol%. Phylogenetic analyses of the 16S rRNA gene sequence indicated that the organism was a member of the domain Bacteria and formed a deep branch within the phylum Aquificae, with Thermovibrio ruber as its closest relative (94·4 % sequence similarity). On the basis of phylogenetic, physiological and genetic considerations, it is proposed that the organism represents a novel species within the newly described genus Thermovibrio. The type strain is Thermovibrio ammonificans HB-1T (=DSM 15698T=JCM 12110T).


2006 ◽  
Vol 188 (9) ◽  
pp. 3345-3356 ◽  
Author(s):  
Craig Everroad ◽  
Christophe Six ◽  
Frédéric Partensky ◽  
Jean-Claude Thomas ◽  
Julia Holtzendorff ◽  
...  

ABSTRACT Chromatic adaptation (CA) in cyanobacteria has provided a model system for the study of the environmental control of photophysiology for several decades. All forms of CA that have been examined so far (types II and III) involve changes in the relative contents of phycoerythrin (PE) and/or phycocyanin when cells are shifted from red to green light and vice versa. However, the chromophore compositions of these polypeptides are not altered. Some marine Synechococcus species strains, which possess two PE forms (PEI and PEII), carry out another type of CA (type IV), occurring during shifts from blue to green or white light. Two chromatically adapting strains of marine Synechococcus recently isolated from the Gulf of Mexico were utilized to elucidate the mechanism of type IV CA. During this process, no change in the relative contents of PEI and PEII was observed. Instead, the ratio of the two chromophores bound to PEII, phycourobilin and phycoerythrobilin, is high under blue light and low under white light. Mass spectroscopy analyses of isolated PEII α- and β-subunits show that there is a single PEII protein type under all light climates. The CA process seems to specifically affect the chromophorylation of the PEII (and possibly PEI) α chain. We propose a likely process for type IV CA, which involves the enzymatic activity of one or several phycobilin lyases and/or lyase-isomerases differentially controlled by the ambient light quality. Phylogenetic analyses based on the 16S rRNA gene confirm that type IV CA is not limited to a single clade of marine Synechococcus.


Zootaxa ◽  
2020 ◽  
Vol 4819 (2) ◽  
pp. 295-315
Author(s):  
HIROSHI KAJIHARA

The heteronemertean Cerebratulus orochi sp. nov. is described based on material collected intertidally at a muddy beach in Akkeshi, northern Japan. For the last 80 years, the species has been confused with Cerebratulus marginatus Renier, 1804; the latter was originally described from the Adriatic and once believed to occur in many places in the northern hemisphere including Japan. Cerebratulus orochi sp. nov. is morphologically different from all the congeners including C. marginatus by the following combination of characters: several layers of diagonal-muscle meshwork coated with connective tissue, proximo-distally distributed in cross section from the distal portion of the body-wall outer longitudinal muscle layer to the cutis-gland zone throughout the anterior portion of the body from the precerebral to the foregut regions; the cephalic vascular system consisting of lateral and mid-dorsal vessels; and the sub-rhynchocoelic vessel possessing a pair of antero-lateral diverticula before the former forks posteriorly into a pair of lower lateral vessels in the post-cerebral, pre-oral region. Previous records of C. marginatus from Japanese waters are no longer considered to be substantiated. Multi-locus phylogenetic analyses based on the mitochondrial 16S rRNA and cytochrome c oxidase subunit I (COI), as well as the nuclear 18S rRNA, 28S rRNA, and histone H3 genes among heteronemerteans comprising the “Cerebratulus clade” indicated that C. orochi sp. nov. was closely related to C. cf. marginatus from the US Pacific coast. A MegaBLAST search at the NCBI website with the 16S rRNA gene sequence from C. orochi sp. nov. followed by a couple of species delimitation analyses suggests that larvae of the species are also distributed in Vostok Bay, Far East Russia.


Phytotaxa ◽  
2020 ◽  
Vol 442 (2) ◽  
pp. 61-79 ◽  
Author(s):  
DENIS DAVYDOV ◽  
SERGEI SHALYGIN ◽  
ANNA VILNET

A cyanobacterial strain isolated from the Svalbard archipelago was studied using morphological, ecological, and molecular approaches. The morphology of natural populations fit well the description of the Leptolyngbya s.l. however, in culture, they formed specific nodules that prevented affiliation to this genus. Further phylogenetic analyses including the 16S rRNA gene and 16S-23S ITS region revealed that the strain corresponds to the genus Nodosilinea. Based on this total evidence approach, we provide here a description of the new taxon Nodosilinea svalbardensis sp. nov.


2007 ◽  
Vol 57 (5) ◽  
pp. 959-963 ◽  
Author(s):  
Jaewoo Yoon ◽  
Mina Yasumoto-Hirose ◽  
Atsuko Katsuta ◽  
Hiroshi Sekiguchi ◽  
Satoru Matsuda ◽  
...  

An obligately aerobic, Gram-negative, non-spore-forming, non-motile, spherical bacterium, designated strain 04OKA010-24T, was isolated from seawater surrounding the hard coral Galaxea fascicularis L., collected at Majanohama, Akajima, Japan, and was subjected to a polyphasic taxonomic study. Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain represented a member of the phylum ‘Verrucomicrobia’ and shared 84–95 % sequence similarity with cultivated strains of ‘Verrucomicrobia’ subdivision 4. Amino acid analysis of the cell-wall hydrolysate indicated the absence of muramic acid and diaminopimelic acid, which suggested that the strain did not contain peptidoglycan in the cell wall. The G+C content of the DNA was 53.9 mol%. MK-7 was the major menaquinone and C14 : 0, C18 : 1 ω9c and C18 : 0 were the major fatty acids. On the basis of these data, it was concluded that strain 04OKA010-24T represents a novel species in a new genus in subdivision 4 of the phylum ‘Verrucomicrobia’, for which the name Coraliomargarita akajimensis gen. nov., sp. nov. is proposed. The type strain of Coraliomargarita akajimensis is 04OKA010-24T (=MBIC06463T=IAM 15411T=KCTC 12865T).


2006 ◽  
Vol 56 (12) ◽  
pp. 2831-2836 ◽  
Author(s):  
Marie Bank Nielsen ◽  
Kasper Urup Kjeldsen ◽  
Kjeld Ingvorsen

A novel alkalitolerant, anaerobic bacterium, designated strain sk.kt5T, was isolated from a metal coupon retrieved from a corrosion-monitoring reactor of a Danish district heating plant (Skanderborg, Jutland). The cells of strain sk.kt5T were motile, rod-shaped (0.4–0.6×2.5–9.6 μm), stained Gram-positive and formed endospores. Strain sk.kt5T grew at pH 7.6–10.5 (with optimum growth at pH 8.0–9.5), at temperatures in the range 23–44 °C (with optimum growth at 35–37 °C), at NaCl concentrations in the range 0–5 % (w/v) (with optimum growth at 0–0.5 %) and required yeast extract for growth. Only a limited number of substrates were utilized as electron donors, including betaine, formate, lactate, methanol, choline and pyruvate. Elemental sulfur, sulfite, thiosulfate, nitrate and nitrite, but not sulfate or Fe(III) citrate, were used as electron acceptors. The G+C content of the DNA was 41.6 mol%. Phylogenetic analyses of the sequence data for the dsrAB genes [encoding the major subunits of dissimilatory (bi)sulfite reductase] and the 16S rRNA gene placed strain sk.kt5T within a novel lineage in the class Clostridia of the phylum Firmicutes. Taken together, the physiological and genotypic data suggest that strain sk.kt5T represents a novel species within a novel genus, for which the name Desulfitibacter alkalitolerans gen. nov., sp. nov. is proposed. The type strain of Desulfitibacter alkalitolerans is sk.kt5T (=JCM 12761T=DSM 16504T).


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