中国湖南角蟾科一新种——桑植角蟾

对采集于湖南桑植县天平山的角蟾标本(CIB200078)与同域分布的相近种尾突角蟾(Megophrys caudoprocta Shen,1994)标本及其他相近种标本比较后发现,该角蟾标本在形态上明显不同于其他物种。其形态特征与尾突角蟾相比:体形小,体长54.7mm;上眼脸外缘三角形突起小;体腹面后部有斑点;犁骨棱弱,末端不膨大,也无犁骨齿;雄性第一、二指背面黑婚刺相对较大,有声囊。与棘指角蟾相比:肛孔上方有一个向后突出的尾突,腹面观可见;雄性第一、二指背面黑婚刺相对较小而密。故将其订为新种:桑植角蟾Megophrys sangzhiensis sp.nov.。     

湖北省两栖动物新纪录——尾突角蟾

2003年7月,在湖北后河国家级自然保护区采集到一批两栖动物标本,经鉴定其中一只为尾突角蟾(Megophrys caudoprocta),系湖北省新纪录种,分类上隶属于两栖纲无尾目角蟾科角蟾属。     

重庆黔江发现尾突角蟾

2022年7月在重庆市黔江区武陵山市级自然保护区采集到1号两栖动物标本,经形态特征比较,与尾突角蟾（Boulenophrys caudoprocta）相似;基于线粒体16Sr RNA和COI基因联合构建布角蟾属（Boulenophrys）部分物种系统发育树,此次采集的角蟾标本与尾突角蟾聚为一支,具有较高的支持率（1/100,贝叶斯法/最大似然超快速引导支持分析值）;基于p-distance估算本次采集的角蟾标本与尾突角蟾湖南模式产地标本间的遗传距离为0%,远小于角蟾属物种间的遗传距离（8.7%～15.9%）。综合形态特征和分子系统发育比较,确定此次采集到的角蟾标本为无尾目（Anura）角蟾科（Megophryidae）布角蟾属的尾突角蟾,系重庆市两栖动物分布新记录种。重庆市尾突角蟾的发现,进一步扩展了该地区的物种名录,拓宽了对尾突角蟾分布范围的认知,为该属区系分类学和系统学提供了新信息,同时为当地生态系统和物种多样性的研究提供了基础信息,对制定更加全面和针对性的保护措施有着积极的促进作用。     

角蟾科Megophryidae系统研究进展

角蟾科Megophryidae是原始无尾两栖类中分化最多的科,分布于亚洲东部、南部及东南部.但角蟾科各类群的分类地位长期以来存在较大争议.本文从形态、染色体、DNA水平方面详细介绍了角蟾科系统学研究的进展;从科的建立、亚科的分类、属的争议、种的争议等各级分类阶元讨论了其研究历史,包括不同阶元的订正、类群的系统发育关系、起源与分化等不同学者的见解;展望了将来的一些研究方向.     

角蟾亚科3物种皮肤的组织学观察

应用石蜡切片和H.E染色技术,对角蟾亚科3个属的代表物种:短肢异角蟾(Xenophrys brachykolos)、宽头短腿蟾(Brachytarsophrys carinense)和小口拟角蟾(Ophryophryne microstoma)的皮肤进行了组织学观察及参数测量比较。分别取头背、体背和体腹3个部位的皮肤进行观察。结果表明,3物种的皮肤基本结构相似,均由表皮和真皮组成,真皮包括疏松层和致密层,疏松层中有大量腺体分布,包括黏液腺和颗粒腺2种。皮肤厚度、各组织层相对厚度以及腺体密度之间存在种间差异和部位差异。在宽头短腿蟾背部皮肤中,发现了与尖吻山角蟾(Megophrys nasuta)皮肤中一种片层状、H.E染色呈蓝色的皮肤真皮骨化结构(osteoderms)很相似的结构;短肢异角蟾皮肤中有明显的钙化层结构,小口拟角蟾皮肤钙化程度较弱。皮肤的骨化和钙化可能具有防止水分流失,抵御干燥的功能。2种内骨骼在角蟾亚科中同时存在,为探讨两栖动物皮肤内骨骼的进化提供了重要的研究基础。     

关于中国角蟾属物种属称订正的建议(无尾目,角蟾科)

简要介绍了角蟾属和异角蟾属的研究历史;通过比较两属的形态学特征,并结合骨骼细胞核型资料和分子系统学的研究结果,证实异角蟾属为有效属;建议将我国的原角蟾属物种归入异角蟾属.     

角蟾科三亚科蝌蚪角质颌的显微结构比较(两栖纲,无尾目)

采用扫描电镜技术研究了角蟾科8种蝌蚪角质颌的显微结构特征和形态特点,阐述了角质颌对蝌蚪觅食方式的影响。实验结果表明:角蟾科蝌蚪的角质颌属于两个不同的类型。拟髭蟾亚科和掌突蟾亚科的蝌蚪具有相似的显微结构特征:角质颌呈厚重的U型,角质化程度高。颌鞘呈基部宽、顶端尖的圆锥形;角蟾亚科的蝌蚪角质颌呈纤弱的弓型,角质化程度低。颌鞘呈基部窄、长而顶端略弯曲的象牙型。进一步的分析发现,8种蝌蚪的颌鞘直径和密度呈显著负相关。这种显微结构的变化趋势也反映出蝌蚪对栖息环境和觅食方式的适应性。     

Ophryophryne属在角蟾科系统发育中所处的位置及拟髭蟾族四属间系统关系

采用最大似然法、贝叶斯法、最大简约法对来自角蟾科Megophryidae(Anura)9属20种及外群2种共30号标本的DNA序列进行了系统发育分析,所用片段为线粒体16S rRNA和cytb基因部分序列。结果表明,用于分析的所有角蟾科物种形成两大支。Ophryophryne、Brachycarsophrys、Atympanophrys同属第一支,前两者的系统关系较近。第二支5属间系统发育关系为(Leptolalax,((Leptobrachium,Vibrissaphora),(Oreolalax,Scutiger)))。     

宁陕齿突蟾的补充描述及地理分布探讨

对采自河南省伏牛山区的角蟾科成体标本和蝌蚪进行形态学观察、测量和统计分析,并依据分子生物学比较结果,确定该标本为宁陕齿突蟾Scutiger ningshanensis.对其进行再研究发现,宁陕齿突蟾伏牛山居群与模式产地居群的主要特征共同之处为,吻端钝圆;瞳孔纵裂;肩背部前方有长方形深褐色斑,背部大疣粒断续相连形成4条纵行肤褶.补充描述了伏牛山居群的形态学特征和生态习性,伏牛山居群雌雄蟾的胸部均有两对密布角质刺的胸腺;雄蟾前臂粗壮,前臂内侧密布黑色角质刺;第1～3指着生黑色婚刺;雌蟾腋下散布大量白色疣粒;成熟卵径3 mm、动物极黄灰色、植物极乳黄色;5月中旬至6月为繁殖季节;蝌蚪发育需越冬.宁陕齿突蟾在河南伏牛山的发现,使角蟾科动物的分布向东延伸了近4个经度.     

角蟾科一新亚种——炳灵角蟾梵净山亚种

报道了角蟾科一新亚种,该亚种具角蟾属特征,与峨眉角蟾种组中的炳灵角蟾(Megophrysbinlingensis)形态特征最为相近,但与该组成员又有明显区别,被命名为炳灵角蟾梵净山亚种(M.b.fanjingmontis subsp.nov.)。本亚种主要鉴别特征为犁骨棱较弱,后端无犁骨齿,上颌有细齿;第一、二指上婚刺细密,趾侧缘膜窄;体腹面斑少,两侧黑褐色长形斑明显;体型较大,雄性头体长大于60.00 mm;趾间具1/3蹼。     

Spermatogenesis in the blue swimming crab, Portunus pelagicus, and evidence for histones in mature sperm nuclei

Spermatogenesis in the blue swimming crab, Portunus pelagicus, is described by light and electron microscopy. The testis is composed of anterior (AT) and posterior (PT) lobes, that are partitioned into lobules by connective tissue trabecula, and further divided into zones (germinal, transformation and evacuation), each with various stages of cellular differentiation. The vas deferens is classified into three distinct regions: anterior (AVD), median (MVD), and posterior (PVD), on the presence of spermatophores and two secretions, termed substance I and II. Based on the degree and patterns of heterochromatin, spermatogenesis is classified into 13 stages: two spermatogonia (SgA and SgB), six primary spermatocytes (leptotene, zygotene, pachytene, diplotene, diakinesis, and metaphase), a secondary spermatocyte (SSc), three spermatids (St 1-3), and a mature spermatozoon. Spermatid stages are differentiated by chromatin decondensation and the formation of an acrosomal complex, which is unique to brachyurans. Mature spermatozoa are aflagellated, and have a nuclear projection and a spherical acrosome. AUT-PAGE and Western blots show that, during chromatin decondensation, there is a reduction of most histones, with only small amounts of H2B and H3 remaining in mature spermatozoa.     

Architecture and function of the lophophore in the problematic brachiopod Heliomedusa orienta (Early Cambrian, South China)

The detailed structure of the lophophore is a key diagnostic character in the definition of higher brachiopod taxa. The problematic Heliomedusa orienta Sun and Hou, from the Lower Cambrian Chengjiang Lagerstätte of Yunnan, southwestern China, has a well-preserved lophophore, which is unlike that of any known extant or extinct brachiopods. Based on a comparative study of lophophore disposition in H. orienta and the extant discinid Pelagodiscus atlanticus, the in- and excurrent pattern and shell orientation of H. orienta are described and discussed. Reconstructions of lophophore shape and function are based on numerous specimens and comparison with P. atlanticus. The lophophore is composed of a pair of lophophoral arms that freely arch posteriorly rather than coiling anteriorly as commonly seen in fossil and recent lingulids. The lophophore is attached to the dorsal lobe of the mantle; it has neither calcareous nor chitinous supporting structures, and is disposed symmetrically on either side of the valve midline. The mouth can be inferred to be located at the base of the two brachial tubes, slightly posterior to the anterodorsal projection of the body wall. The lophophoral arms bear laterofrontal tentacles with a double row of cilia along their lateral edge, as in extant lingulid brachiopods. The main brachial axes are also ciliated, which presumably facilitated transport of mucous-bound nutrient particles to the mouth. The unique organization of the lophophore in Heliomedusa is not like any known fossil and living brachiopods. This clearly demonstrates that H. orienta is not a member of any crown group. It is here considered as a member of the brachiopod stem group, which challenges recent interpretations of a close discinid affinity.     

Ultrastructural study of the male gamete of Glossobothrium sp. (Cestoda: Bothriocephalidea: Triaenophoridae) a parasite of Schedophilus velaini (Perciformes: Centrolophidae) in Senegal

This paper describes the ultrastructure of the male gamete of Glossobothrium sp. (Bothriocephalidea: Triaenophoridae). The mature spermatozoon of Glossobothrium sp. is filiform and possesses two axonemes, a single helicoidal crested body, a parallel nucleus, parallel cortical microtubules and granules of glycogen. In Glossobothrium sp. we describe for first time a 200-250 nm thick crest-like body in the Bothriocephalidean. The anterior part of the spermatozoon exhibits a ring of 27 electron-dense cortical microtubules encircling the first axoneme. This structure persists until the appearance of the second axoneme. When the ring of electron-dense cortical microtubules disappears, the spermatozoon exhibits two bundles of thin cortical microtubules. The posterior part of the spermatozoon contains the posterior extremity of the second axoneme, the posterior extremity of the nucleus and few cortical microtubules. Soon nucleus disappears and the axoneme is disorganized. Thus the posterior extremity of the spermatozoon of Glossobothrium sp. exhibits only singlets produced by the disorganization of the doublets of the second axoneme and few cortical microtubules. This type of posterior extremity of the mature spermatozoon has never been described previously in the Triaenophoridae.     

Descriptions of Four New Species of Criconematoidea (Tylenchina: Nemata) from Southern Chile

Four new species of Criconematoidea are described from Hoste Island, Chile. Criconema certesi n. sp. is distinguished by the fine, spine-like, cuticular extensions on body annuli; projection of annuli into rows of scales on posterior part of body; single, smooth, labial annulus set off by short collar from second (first body) annulus which is about same diameter as first (labial) annulus. Male with prominent caudal alae, slender curved spicules, and four incisures in lateral field. Ogma terrestris n. sp. is distinguished by small scales with rounded tips bearing minute, short bristles; scales number 21 at mid-body; and first (labial) annulus rounded, not retrorse, not set off from succeeding annuli, narrower in diameter from second (first body) annulus. Hemicycliophora macrodorata n. sp. is distinguished by its large size (L = 1.52 [1.28-1.72] mm); large stylet (146 [127-161] μm); annuli = 297 (280-315); tail slightly spicate, lateral field with or without interruptions of incisures, occasional anastomoses; and males with U-shaped spicules. Paratylenchus fueguensis n. sp. is distinguished by its prominent stylet with large, rounded knobs (4-5 μm across); cephalic region rounded not at all set off; lateral field with four incisures; lateral vulvar membranes present; and male tail short, strongly curved (almost 180°) ventrad.     

Description of Afenestrata koreana n. sp. (Nematoda: Heteroderinae), a Parasite, of Bamboo in Korea

Afenestrata koreana n. sp. collected from roots of bamboo (Phyllostachys pubescens) in Gyeongnam Province in the southern part of the Korean peninsula is described and illustrated. Its primary differentiating characteristics are a globose to subspherical body in adults with a prominent neck and terminal cone, thick cuticle, terminal vulva, and deep vagina. Fenestra, bullae, and underbridge are absent. The anus is on the immediate posterior side of the cone. Superficial small tubercules cover all the terminal cone area. The new species differs markedly from the other two known species in the genus, specifically in having three incisures in the lateral field of juveniles and a shorter stylet length in juveniles and adults. The male is unknown.     

A remarkable new genus of Atalophlebiinae (Ephemeroptera: Leptophlebiidae) from the Neotropics

An unusual species of Leptophlebiidae is described based on males, females, and nymphs from Rio de Janeiro State, Brazil. As a consequence of its distinct characteristics on all stages, a new genus is established. The new genus can be distinguished from other South American Leptophlebiid genera mostly by: Adults: vein MA of fore wings asymmetrical; hind wings with costal projection well developed, Sc ending at cross vein near costal projection; tarsal claws dissimilar, one blunt other acute; projections of styliger plate forming two well developed lobes with rounded apex, ventrally obstructing view of the penes; penes fused on basal half, each lobe with a ventral furrow and a long and slender spine directed anteriorly. Nymphs: Head prognathous, wider than labrum; labrum with prominent median emargination, with three subtle crenulations; body flattened; hind wings pads present; tarsal claws with over 20 denticles, subapical denticle much larger than remaining denticles; gills long and narrow, present on abdominal segments I-VII; posterolateral projections present on abdominal segments VIII-IX. Phylogenetic analyses conducted based on a previously published data matrix that included other South America leptophlebiid genera placed Poranga nessimiani gen. nov. et sp. nov. as sister to Bessierus + Perissophlebioides. In most analyses this clade was recovered within the Farrodes complex. Nymphs of the new taxa are particularly similar to Bessierus, whereas adults share the very acute costal projection on hind wings seen in non-dipterous members of the Farrodes complex.     

A combinatorial enhancer recognized by Mad, TCF and Brinker first activates then represses dpp expression in the posterior spiracles of Drosophila

A previous genetic analysis of a reporter gene carrying a 375-bp region from a dpp intron (dppMX-lacZ) revealed that the Wingless and Dpp pathways are required to activate dpp expression in posterior spiracle formation. Here we report that within the dppMX region there is an enhancer with binding sites for TCF and Mad that are essential for activating dppMX expression in posterior spiracles. There is also a binding site for Brinker likely employed to repress dppMX expression. This combinatorial enhancer may be the first identified with the ability to integrate temporally distinct positive (TCF and Mad) and negative (Brinker) inputs in the same cells. Cuticle studies on a unique dpp mutant lacking this enhancer showed that it is required for viability and that the Filzkorper are U-shaped rather than straight. Together with gene expression data from these mutants and from brk mutants, our results suggest that there are two rounds of Dpp signaling in posterior spiracle development. The first round is associated with dorsal-ventral patterning and is necessary for designating the posterior spiracle field. The second is governed by the combinatorial enhancer and begins during germ band retraction. The second round appears necessary for proper spiracle internal morphology and fusion with the remainder of the tracheal system. Intriguingly, several aspects of dpp posterior spiracle expression and function are similar to demonstrated roles for Wnt and BMP signaling in proximal-distal outgrowth of the mammalian embryonic lung.     

Descriptions of Eumonhystera borealis n. sp., Sphaerolaimus occidentalis n. sp., and a Redescription of S. gracilis de Man 1876 (Nemata) from Bothnian Bay,Baltic Sea

The free-living nematodes Eumonhystera borealis n. sp., Sphaerolaimus occidentalis n. sp., and S. gracilis de Man 1876 from Bothnian Bay in the northern Baltic Sea are described and illustrated. Eumonhystera borealis n. sp. differs from other species by its small body size (314-393 μm), narrow body (a = 37-49), and large anterior amphids. In Sphaerolaimus occidentalis n. sp. the amphids are posterior to the buccal cavity, and it differs from other similar species by having two sclerotized rings in the posterior part of the buccal cavity. An intersex is reported for S. gracilis. Sphaerolaimus gracilis is cannibalistic or a predator of other species, with a preference for E. borealis n. sp. Sphaerolaimus occidentalis n. sp. coexists with S. gracilis at depths of 80 m but not at 12 m.     

Structural characteristics of a novel antifreeze protein from the longhorn beetle Rhagium inquisitor

Antifreeze proteins (AFPs) are characterized by their capacity to inhibit the growth of ice and are produced by a variety of polar fish, terrestrial arthropods and other organisms inhabiting cold environments. This capacity reflects their role as stabilizers of supercooled body fluids. The longhorn beetle Rhagium inquisitor is known to express AFPs in its body fluids. In this work we report on the primary structure and structural characteristics of a 12.8 kDa AFP from this beetle (RiAFP). It has a high capacity to evoke antifreeze activity as compared to other known insect AFPs and it is structurally unique in several aspects. In contrast to the high content of disulfide bond-formation observed in other coleopteran AFPs, RiAFP contains only a single such bond. Six internal repeat segments of a thirteen residue repeat pattern is irregularly spaced apart throughout its sequence. The central part of these repeat segments is preserved as TxTxTxT, which is effectively an expansion of the TxT ice-binding motif found in the AFPs of several known insect AFPs.     

Descriptions of two new silversides, Hypoatherina golanii and Hypoatherina lunata, from the Indo-West Pacific (Atheriniformes: Atherinidae)

Two new atherinid fishes, Hypoatherina golanii and Hypoatherina lunata, are described based on specimens collected from the wide range of the Indo-West Pacific. The former species is known from the Red Sea and was confused with Hypoatherina barnesi because it has a somewhat wide midlateral band and overlapping meristic counts. Hypoatherina golanii is distinguished from its congeners by the midlateral scales with an indented posterior margin, posterior margin of anterior predorsal scales with a spatular outgrowth, posterior margin of axillary scales without a distinct projection, and posterior end of maxilla not slanted downward. Hypoatherina lunata is distributed in the waters of southern Japan (Okinawa and Kagoshima prefectures) and Indonesia (North Sulawesi, Maluku, and Papua), but was confused with Hypoatherina woodwardi. Hypoatherina lunata is distinguished from its congeners in having a distinct crescent marking in front of the eye and the anus usually situated anterior to the tip of the pelvic fin.