广西靖西寒武纪三叶虫Tamdaspis jingxiensis sp.nov.的个体发育及畸形

描述采自广西靖西果乐剖面三都组一三叶虫新种Tamdaspis jingxiensis sp.nov.,根据该种三叶虫完整标本的背壳特征,认为Liushuicephalus Luo,1983是Tamdaspis Lisogor,1977的晚出异名。同时描述T.jingxiensis sp.nov.的个体发育过程和两块畸形标本,并认为该畸形是因被捕食者咬伤而形成的。     

人类活动对广西合浦海草床服务功能价值的影响

近年来,中国海草生态系统受到严重破坏。本文以广西合浦海草床生态系统为例,采用1980—2005年当地统计资料,综合运用生态经济学的基本理论,以海草床的食物生产、调节大气、生态系统营养循环、净化水质、维持生物多样性和科学研究功能作为指标体系,对人类活动造成合浦海草床生态系统的价值损失进行了初步估算。结果表明,从1980—2005年,合浦海草床由于人类活动造成的价值损失为34657.95万元,损失率为71.97%。直接利用价值增加了4452.88万元,而间接利用价值损失为39110.83万元,损失率高达81.82%。说明人类对合浦海草床的开发利用强度增大趋势明显。     

广西外来入侵植物

通过调查和文献整理,初步确认广西有外来入侵植物114种,隶属于36科80属,其中以菊科的种类最多,有26种。外来入侵植物来源于世界各地,以来源于美洲居多,有87种,占76.3%。入侵植物以草本植物为主,有90种,占78.9%。外来入侵植物主要通过有意引入和无意传入等方式入侵广西。它们的入侵,特别是一些恶性杂草的入侵,给广西农业、林业、人类健康以及生态环境带来巨大的负面影响。加强对外来入侵植物的调查和评估,恢复当地植被和物种的多样性,开展有害生物风险分析是防范外来入侵植物的有效途径。     

Huffmanela selachii n. sp. (Nematoda: Trichosomoididae: Huffmanelinae): A new species infecting the skin of the great hammerhead shark (Sphyrna mokarran) and the blacktip reef shark (Carcharhinus melanopterus) in the Arabian Gulf,off-shore Saudi Arabia

From January 2017 - December 2019, 75 out of 850 (8.8 %) great hammerhead sharks from the Arabian Gulf had skin lesions of black irregular discolorations on the ventral surface of the head. The lesions consisted of pencil-like lineations often advancing forward by about 2 mm in back-and-forth looped scribbles often forming a relatively linear bands of about 5–7 cm wide. Similar lesions were also found in the blacktip reef shark from the same area within the same period, and consisted of straight to irregular black lines, extended indiscriminately across the skin of the sharks. Microscopic examination of the skin revealed the presence of dark-brown eggs exhibiting the spindle or ellipsoidal eggs characteristic of Huffmanela sp. The morphometrics of eggs from both hosts were similar (62.9–89.9 μm long and 29.3–56.1 μm wide). The eggshells were smooth with polar plugs protruding or not, with an abruptly truncated crown-like or shoulder-like collar surrounding the plug. The eggs were only found in the epidermal layer of the skin. Based on the unique morphometrics of the eggs, we report a new species, named: Huffmanela selachii n. sp.. This appears to be the first report of Huffmanela from either the great hammerhead shark or the blacktip reef shark, and the third reported Huffmanela in sharks from the Arabian Gulf. It is also one of few species reported from connecting waters of the greater Indian Ocean. This new finding contributes to our understanding of the diversity and ubiquity of Huffmanela sp. in marine creatures.     

Assemblage structure,vertical distributions and stable-isotope compositions of anguilliform leptocephali in the Gulf of Mexico

In August 2007, October 2008 and September–October 2010, 241 Tucker trawl and plankton net tows were conducted at the surface to depths of 1377 m at six locations in the northern and eastern Gulf of Mexico (GOM) to document leptocephalus diversity and determine how assemblage structure, larval size, abundance and isotopic signatures differ across the region and with depth. Overall, 2696 leptocephali representing 59 distinct taxa from 10 families were collected. Five families accounted for 96% of the total catch with Congridae and Ophichthidae being the most abundant. The top four most abundant species composed 59% of the total catch and included: Ariosoma balearicum, Paraconger caudilimbatus, Rhynchoconger flavus and Ophichthus gomesii. Four anguilliform species not previously documented in the GOM as adults or leptocephali were collected in this study, including Monopenchelys acuta, Quassiremus ascensionis, Saurenchelys stylura and one leptocephalus only known from its larval stage, Leptocephalus proboscideus. Leptocephalus catches were significantly greater at night than during the day. Catches at night were concentrated in the upper 200 m of the water column and significantly declined with increasing depth. Leptocephali abundances and assemblages were significantly different between sites on the upper continental slope (c. 500 m depth) and sites on the middle to lower continental slope (c. 1500–2300 m). Sites on the lower continental slope had a mixture of deep-sea demersal, bathypelagic and coastal species, whereas upper-slope sites contained several numerically dominant species (e.g., A. balearicum, P. caudilimbatus) that probably spawn over the continental shelf and upper slope of the GOM. Standard lengths of the four dominant species differed between sites and years, indicating heterochronic reproduction and potential larval source pools within and outside of the GOM. Stable-isotope analyses (δ¹³C and δ¹⁵N) conducted on 185 specimens from six families revealed that leptocephali had a wide range of isotopic values at the family and size-class levels. Species in the families Muraenidae, Congridae and Ophichthidae had similar δ¹⁵N values compared with the broad range of δ¹⁵N values seen in the deep-sea families Nemichthyidae, Nettastomatidae and Synaphobranchidae. Stable-isotope values were variably related to length, with δ¹⁵N values being positively size correlated in ophichthids and δ¹³C values being negatively size correlated in A. balearicum and P. caudilimbatus. Results suggest that leptocephali feed in various water depths and masses, and on different components of POM, which could lead to niche partitioning. Ecological aspects of these important members of the plankton community provide insight into larval connectivity in the GOM as well as the early life history of Anguilliformes.     

Detecting Karenia brevis blooms and algal resuspension in the western Gulf of Mexico with satellite ocean color imagery

Blooms of the toxic dinoflagellate, Karenia brevis, have had detrimental impacts on the coastal Gulf of Mexico for decades. Detection of Karenia brevis blooms uses an ecological approach based on anomalies derived from ocean color imagery. The same anomaly product used in Florida produces frequent false positives on the Texas coast. These failures occurred during wind-driven resuspension events. During these events resuspension of benthic algae significantly increases chlorophyll concentrations in the water, resulting in confusion with normal water column phytoplankton, such as Karenia. A method was developed to separate the resuspended chlorophyll from the water column chlorophyll, decreasing the false positives used with the detection method.     

广西景天科景天属植物小志

该文基于文献考证、馆藏标本鉴定及野外调查，对广西景天属(Sedum L.)植物进行了系统的梳理，对景天属植物物种多样性进行概述，确定目前分布有17种，其中有6个新记录种。该文概述了广西景天属植物物种多样性，订正了藓状景天(S.polytrichoides Hemsl.),简述了6个新记录种，即钝萼景天(S.leblancae Hamet.)、黎平景天(S.lipingense R. B. Zhang, D. Tan&R. X. Wei)、龙泉景天(S.lungtsuanense S. H. Fu)、圆叶景天(S.makinoi Maxim.)、细小景天(S.subtile Miq.)、土佐景天(S.tosaense Makino),并提供其形态特征集要与彩色照片。该文还对广西景天属植物的多样性以及资源潜在利用价值等进行了讨论，并附有分种检索表和各个分类群在广西的分布情况，为该属后续的研究与利用提供了本底资料。     

Two new Marina (Leguminosae) from the southern Baja California peninsula, Mexico

Marina victoriae andM. brevis are newly described species from the southern Baja California peninsula, Mexico. The former is a perennial herb locally abundant in the eroded hillsides at the foothills of Sierra de la Victoria, where an oak woodland and a dry tropical forest meet. The latter is an elusive ephemeral inhabiting a narrow strip of land between the mangroves and the desert scrub on an island in the Gulf of California. These two new species belong to the seriesChrysorrhizae, a group native to the Gulf of California basin.     

Mussel beds in deeper water provide an unusual situation for competitive interactions between the seastars Leptasterias polaris and Asterias vulgaris

The common seastars Leptasterias polaris and Asterias vulgaris show competitive interactions in shallow subtidal communities in the northern Gulf of St. Lawrence, particularly during summer when aggregations of the two seastars forage on mussel beds at 1-2 m in depth. We examined interactions between the two seastars in a different situation, in a mussel bed at 6 m in depth (a rare situation in this region). In the deeper mussel bed, seastars were three times more abundant than in the shallower beds, and the mussels were larger. The deeper bed disappeared rapidly due to the intense predation. Although decreased prey abundance should have favored interference interactions, we did not detect either partitioning of mussels by size or avoidance of A. vulgaris by L. polaris as previously reported when mussels are in short supply in shallower water. The lack of an avoidance behavior by L. polaris, together with the higher proportion of L. polaris than A. vulgaris that were feeding, suggests that in this situation, the dominance of A. vulgaris (observed in shallower water) is attenuated, or that L. polaris may dominate.     

广西陆栖兽类动物分布格局及区划探讨

根据广西陆栖兽类种类,数量和分布特点。结合自然地理条件,探讨了广西陆栖兽类支持发布格局,并将广西兽类地理区划为7个小区：Ⅰ桂西南缘山地小区;Ⅱ桂南沿海台地平原小区;Ⅲ桂西南丘陵盆地小区;Ⅳ桂中丘陵山地小区;Ⅴ桂中及桂东低丘台地,山地,谷地小区;Ⅵ桂西北岩溶山原盆坝小区;Ⅶ桂东北南岭山地小区。广西陆栖兽类区域分化不明显,而受地形因素的更显著,海拔较高的桂西,北边缘山地区系成分较为近似,而与东部和南部沿海低海拔的丘陵,低山及盆地形成较明显的差异。盆地内弧形山脉的动物区系别具特色。