A long‐standing hypothesis for the adaptive radiation of macrostomatan snakes is that their enlarged gape – compared to both lizards and basal snakes‐enables them to consume ‘large’ prey. At first glance, this hypothesis seems plausible, or even likely, given the wealth of studies showing a tight match between maximum consumed prey mass and head size in snakes. However, this hypothesis has never been tested within a comparative framework. We address this issue here by testing this hypothesis in 12 monophyletic clades of macrostomatan snakes using recently published phylogenies, published maximum consumed prey mass data and morphological measurements taken from a large sample of museum specimens. Our nonphylogenetically corrected analysis shows that head width – independent of body size – is significantly related to mean maximum consumed prey mass among these clades, and this relationship becomes even more significant when phylogeny is taken into account. Therefore, these data do support the hypothesis that head shape is adapted to prey size in snakes. Additionally, we calculated a phylogenetically corrected morphological variance–covariance matrix to examine the role of morphological integration during head shape evolution in snakes. This matrix shows that head width strongly covaries with both jaw length and out‐lever length of the lower jaw. As a result, selection on head width will likely be associated with concomitant changes in jaw length and lower jaw out‐lever length in snakes.

The Vietnamese Mekong Delta (VMD) comprises extensive river and canal networks, both natural and man‐made, and has a history of extensive land use change and development. The delta's wetlands are under considerable ecological stress because of hydrological changes, agricultural and aquaculture development, urban and industrial pollution, climate change, and upstream water resource development. In this paper, we review the current threats and challenges to the conservation and management of the wetlands in the VMD. We recommend that the current water management practices of the Ramsar‐listed Lang Sen Wetland Reserve are changed so that the natural flood regimes are reinstated and the risks to the community from forest fires are managed. Ongoing investment is needed to support further research, set up long‐term monitoring, and to develop hydrodynamic models for the Lang Sen Wetland Reserve so that management and conservation efforts can achieve the specific objectives for the wetland. This approach may be useful for managing other wetlands across the VMD.

Freshwater shrimp of the family Atyidae De Haan, 1849 have been studied in Vietnam for more than a century. A total of 24 species of atyid shrimps from the genera Caridina H. Milne Edwards, 1837, Neocaridina Kubo, 1938, Atyopsis Chace, 1983 have been recorded from Vietnam. With 22 species, the majority are from the genus Caridina. In 2013, Karge and Klotz mentioned the occurrence of four yet undescribed species belonging to Paracaridina Liang, Guo & Tang, 1999 in Vietnam without taxonomic details. In general, studies of freshwater atyids in Vietnam are limited and most Vietnamese taxa await a taxonomic revision. The available data do not fully reflect their estimated species diversity in the country and distribution data are deficient. Here, we focus on four species of atyid shrimps from two genera, viz. Caridina cantonensis Yu, 1938, C. lanceifrons Yu, 1936, C. serrata Stimpson, 1860 and Neocaridina palmata (Shen, 1948), all described from China and have been reported to occur in Vietnam. The previous reports on the occurrence of these species in Vietnam are largely unreliable due to taxonomic confusion. To contribute to the knowledge of these taxa, we provide the first verified distribution records of the four species in the country with some taxonomic remarks. This study shows the first taxonomically-verified distribution data of four atyid shrimp species originally described from China, but also reported from Vietnam, albeit under various species names and, in some cases, erroneously. These data allow the first meaningful discussion of the distribution in light of the reproductive strategy of these four species and, in conjunction with the taxonomic remarks, will contribute to the knowledge of these taxa. As a result of this research and data from previous studies, we now consider all four species as widespread and non-endemic, but land-locked (with a complete freshwater life cycle). In Vietnam, all four species are confined to the northern half of the country. Beyond Vietnam, we provide the first records for Caridina lanceifrons from southern Thailand, which suggests a major sampling gap in Indochina.

Nội dung bài viết này chỉ đề cập đến đa dạng thành phần loài, Trùng bánh xe trong một số thủy vực nội địa ở Nam bộ và những ghi nhận mới cho khu hệ động vật nổi Việt Nam. PHƯƠNG PHÁP NGHIÊN CỨUCác loài Trùng bánh xe được phân tích trong mẫu động vật nổi thu thập từ các chương trình nghiên cứu khoa học, quan trắc thủy sinh vật từ năm 2005-2011. Vị trí, số lượng và thời gian thu mẫu được mô tả trong bảng 1.Mẫu động vật nổi được thu bằng lưới vớt động vật kiểu Juday, có kính thước mắt lưới 75 m, thu mẫu bằng cách kéo lưới trên bề mặt lặp lại từ 1-5 lần. Các mẫu động vật nổi và thực vật nổi sau khi thu được lắc đều phần đáy của lưới để đạt tới thể tích 100-150 ml và cho vào chai nhựa có thể tích 250 ml. Mẫu được cố định ngay sau khi thu bằng formaldehyd với nồng độ 4-5%. Các chai nhựa được ghi nhãn với các thông tin về thời gian thu mẫu, ký hiệu mẫu, loại mẫu... Tại phòng thí nghiệm, các xác bã thực vật, mảnh vụn có kích thước lớn được loại bỏ. Sau đó, các mẫu được lọc lại lần nữa với tốc độ chậm bằng ống xiphong có lưới lọc với kích thước mắt lưới 10 µm đến thể tích 50 ml. Mẫu sau khi lọc được phân tích thành phần loài và giải phẩu hình thái dưới kính hiển vi quang học đảo ngược có độ phóng đại từ 100-400. Định danh và mô tả các loài Trùng bánh xe dựa vào các tài liệu phân loại trong và ngoài nước. Sử dụng phần mềm Primer V6 để tính chỉ số tương đồng của thành phần loài Trùng bánh xe giữa các thủy vực. Các loài ghi nhận mới được vẽ qua ống kính vẽ và số hóa bằng phần mềm Adobe Illustrator CS5.

The occurrence of Larnaudia Bott, 1966 in southern Vietnam remains obscure. Although some previous studies described the presence of Larnaudialarnaudii A. Milne-Edwards, 1869 in Vietnam, our analysis of freshwater crab specimens collected at many locations in southern Vietnam revealed that Neolarnaudia Türkay Naiyanetr, 1987, but not Larnaudia Bott, 1966, is present in southern Vietnam. In this study, we recorded two species of Neolarnaudia, N. phymatodes (Kemp, 1923) and N. botti Türkay & Naiyanetr, 1987 in southern Vietnam. Neolaurnaudia phymatodes was poorly knownsince the original description, and is, thus, re-described here. This species can be distinguished from all other Neolarnaudia species by a suite of characters; carapace broader, frontal area with many granules, supraorbital margingranulated, suborbital and pterygostomian regions and merus of third maxillipedcovered with many granules, terminal segment of Gonopod 1 strongly curved inwards and covered with many pubescences, lateral margin of telsonstrongly concaved. Citation: Do Van Tu, Dang Van Dong, Le Van Tho, Phan Doan Dang, 2017. Review of two genera of freshwater crabs, Larnaudia Bott, 1966 and Neolarnaudia Türkay & Naiyanetr, 1987 (Crustacea: Decapoda: Potamidae) with redescription Neolarnaudiaphymatodes (Kemp, 1923) from Southern Vietnam. Tap chi Sinh hoc, 39(4): 398-405. DOI: 10.15625/0866-7160/v39n4.8464.*Corresponding author: dovantu.iebr@gmail.com, dovantu@iebr.vast.vnReceived 19 September 2017, accepted 12 December 2017