陕南早寒武世具口部的磷酸盐化Punctatus及其胚胎化石

报道陕西南部灯影组宽川铺段地层中发现的Punctatus锥体标本、保留精美软组织特征的口部标本和可能的胚胎标本。对Punctatus软组织及整体形态功能研究表明,Punctatus在分类上可能更接近于腔肠动物的水螅型,代表初具原始触手的腔肠动物早期演化类型。在上万枚与Punctatus共生的球状化石中,发现若干枚可能的原肠期胚胎及胚胎发育晚期标本,在此基础上提出PunctatusemeiensisHe,1980花冠状口部可能经历的胚胎发育序列。     

New material of Pleistocene cats (Carnivora, Felidae) from Southern South America, with comments on biogeography and the fossil record

In this paper the systematic position and age of several Pleistocene cat remains found in southern South American are studied, in an attempt to more fully document the scarce record of the group and clear up their obscure Quaternary history. The fossils are compared with a large sample of recent specimens by means of qualitative and quantitative characters, as well as multivariate methods (discriminant analysis). The age of previous records is restricted using recent chronostratigraphic and biostratigraphic studies. Ly. colocolo is recorded in the late Ensenadan (0.78-0.5 Ma BP) and Bonaerian/Lujanian (0.5 Ma-8.5 Ka BP) ages of the Pampean Region (Argentina) and in the late Pleistocene or Holocene of Tierra del Fuego (Chile). An incomplete hemimandible found in the Bonaerian of the Pampean Region is referred to cf. Herpailurus and could be the earliest record of this lineage. Two other remains could belong to On. geoffroyi, but their incompleteness and some differences prevent their assignation to this recent species. The age of “Felis” vorohuensis is restricted to the late Ensenadan. The fossil record of the Ocelot Lineage is very fragmentary, but it is at least as old as late Ensenadan. Taphonomic biases are responsible for this poor fossil record and this fact could partially explain the hiatus with respect to the timing estimated by molecular divergence. The combination of data suggests that Ly. colocolo, On. guigna, On. geoffroyi and Oreailurus jacobita speciated in South America, supporting previous opinions. If the molecular divergence dates are right the recent diversity of this group could be explained by a minimum of five to six immigrations.     

An analysis of the mole rats (Mammalia: Rodentia) from Langebaanweg (Mio-Pliocene, South Africa)

A study of the taphonomy and age profiles of the mole rat population from Langebaanweg ‘E’ Quarry was undertaken in order to see if these subterranean rodents had been accumulated by predation (coprocoenosis hypothesis) or as a result of drowning in their burrows during a flood event (catastrophocenosis hypothesis). Previous research has cited the bathyergids as being the most common rodent at Langebaanweg, however, a comprehensive study of new micromammal material indicates that murids, rather than mole rats, dominate most of the assemblages. The concentration of mole rat remains in many of the fossil-bearing levels at Langebaanweg is, nevertheless, still extremely high compared to other fossil sites or predation assemblages in the area. A taphonomic examination of mole rat incisor surfaces indicates that digestion occurs on between 44% and 54% of incisors in the different assemblages, and this, together with the degree of digestion suggests that category 1 and category 2 predators had been responsible for the accumulation of the fossil mole rat assemblages. The absence of rounding, polishing or weathering on the fossils indicates that there has been little or no transport by water, and that burial of the bones was rapid. Breakage and damage to the anterior portion of many of the mandibles made it impossible to accurately assess the age of the older mole rats, and the majority of mandibles could provide only a minimum age of the animal at the time of death. The age profile indicates that very young individuals are missing from the assemblages. This allows for refutation of the previously made suggestion that flooding was responsible for the death of the majority of Langebaanweg mole rats and also introduces the possibility that Bathyergus hendeyi may have been a social animal, unlike extant bathyergids which are solitary.     

Himantura lobistoma, a new whipray (Rajiformes: Dasyatidae) from Borneo, with comments on the status of Dasyatis microphthalmus

A new long-snouted whipray, Himantura lobistoma, is described on the basis of seven specimens collected from the southeastern sector of the South China Sea, off western Borneo. It belongs to a subgroup of Himantura species provisionally defined herein as the “uarnacoides” complex that includes five nominal species: H. chaophraya, H. granulata, H. hortlei, H. pastinacoides, and H. uarnacoides. These whiprays all have a similar lateral disc shape (i.e., pectoral-fin apices broadly rounded rather than narrowly rounded or angular), a plain colouration (i.e., usually uniform light to dark brown dorsally, and pale or whitish ventrally with or without a dark margin), a long and slender whiplike tail, and platelike denticles in a broad dorsal band in adults. Himantura lobistoma can be distinguished from the superficially similar H. hortlei by its highly protrusible mouth and pelvic girdle with prominent lateral prepelvic processes. It differs from other members of the “uarnacoides” complex by a combination of internal and external morphological characteristics (e.g., having an extremely elongate snout and very small eyes). Another long-snouted stingray from the region, Dasyatis microphthalmus Chen, inadequately described and known only from the lost holotype, is considered a nomen dubium. It had been assigned to Himantura based on the absence of an obvious ventral cutaneous tailfold but may be conspecific with D. acutirostra.     

Conservation value of degraded habitats for forest birds in southern Peninsular Malaysia

Clearance of tropical forest for agricultural purposes is generally assumed to seriously threaten the survival of forest species. In this study, we quantified the conservation value, for forest bird species, of three degraded habitat types in Peninsular Malaysia, namely rubber tree plantations, oil palm plantations, and open areas. We surveyed these degraded habitats using point counts to estimate their forest bird species richness and abundance. We assessed whether richness, abundance, and activities of different avian dietary groups (i.e. insectivores and frugivores) varied among the habitats. We identified the critical habitat elements that accounted for the distribution of forest avifauna in these degraded habitats. Our results showed that these habitats harboured a moderate fraction of forest avifauna (approximately 46–76 species) and their functions were complementary (i.e. rubber tree plantations for moving; open habitats for perching; shrubs in oil palm plantations for foraging). In terms of species richness and abundance, rubber tree plantations were more important than oil palm plantations and open habitats. The relatively high species richness of this agricultural landscape was partly due to the contiguity of our study areas with extensive forest areas. Forecasts of forest-species presence under various canopy cover scenarios suggest that leaving isolated trees among non-arboreal crops could greatly attract relatively tolerant species that require tree canopy. The conservation value of degraded habitats in agricultural landscapes seems to depend on factors such as the type of crops planted and distance to primary forest remnants.     

贵州省荔波发现百花锦蛇

2010年7月～2012年8月,在贵州省荔波南方喀斯特世界自然遗产地进行脊椎动物物种多样性调查时,分别在板寨、瑶山、翁昂和洞塘采集到游蛇科蛇类标本共5条,经分类鉴定为锦蛇属(Elaphe)的百花锦蛇(E.moellendorffi),为该物种在贵州省内首次发现,增加了其在国内的分布点.     

Aagaardia,a New Holarctic Orthoclad Genus (Diptera: Chironomidae)

Diagnoses of all stages of the new genus Aagaardia are given. The genus includes A. sivertseni (Aagaard), originally described in Eukiefferiella Thienemann, from Norway and Finland and described in all stages; A. protensa sp.n. from Finland and A. triangulata sp.n. from Turkey described as male imagines; and A. longicalcis sp.n. from Canada described in both sexes. The male imagines share bare eyes, strong punctation on wings, bare squama, extended costa, triangular gonostylus and two groups of extremely strong and sclerotized virga. The pupa and the female genitalia show relationship with Paratrissocladius Zav[rcirc]el, while the larva is very similar to the larvae of Psilometriocnemus Sæther and Platysmittia Sæther. Parsimony analyses suggest that Aagaardia forms the plesiomorphic sister genus to the rest of the Heterotrissocladius group combined.     

Lower Abundance of Ammonia-Oxidizing Archaea Than Ammonia-Oxidizing Bacteria Detected in the Subsurface Sediments of the Northern South China Sea

Diversity and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in samples of the northern South China Sea subsurface sediment were assessed by analyzing the amoA gene sequences retrieved from the samples. The microbial diversity was assessed using rarefaction and phylogenetic analyses. The deep-sea subsurface sediments harbored diverse and distinct AOA and AOB communities, but the abundance of AOA was lower than that of AOB, consistent with many other studies about bacteria and archaea in subsurface sediments. Diversity of AOA shown in the OTUs and Shannon index was correlated with the concentration of nitrite in the Pearson analysis, but no obvious relationships between the diversity or abundance of AOB and the physicochemical parameters could be identified in the present study, indicating the concentration of ammonium may not be an important factor to determine the diversity and abundance of ammonia-oxidizing prokaryotes in the subsurface sediments. Additionally, Nitrosomonas-like AOB was found to be dominant in subsurface sediments of the northern South China Sea showing a different adaption strategy comparing with some Nitrosospira-like AOB lineages. Concentration of nitrite was correlated with diversity of AOA, but no correlations between diversity and abundance of AOB and the physicochemical parameters were established in the study. Supplementary materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental files.