Figure 1: Amplexus and mating aggregations in Adenomus kandianus. (a) An amplexed pair out of water, showing axillary amplexus. (b–c) A large mating aggregation in slow water, sandy-bottomed refuge in a stream bordering the Peak Wilderness sanctuary.
Endemic to Sri Lanka, genus Adenomus contains two torrent-associated toad species whose ecology and natural history in the wild is virtually unknown. Adenomus kelaartii is relatively common, with a wide geographic distribution. Its sister species, A. kandianus, however, is restricted to two isolated populations in fast-disappearing montane and sub-montane forests. Formally declared extinct after not being recorded for over a century, a few A. kandianus were rediscovered in 2012 and redescribed as "the world's rarest toad". Here we report the results of a two-year study of the occurrence, habits and habitat associations of adult and larval A. kandianus using both general surveys and quadrat sampling. We show this to be a secretive species with a patchy distribution. Non-breeding female toads dwell in primary-forest habitats, but after heavy and sudden downpours they form large mating congregations in large streams. Amplexed pairs swim synchronously, enabling them to traverse fast currents. Egg-laying sites remain unknown, but the ability to dive and vocalize underwater, and characteristics of the eggs, suggest that they lay eggs in dark recesses of the stream. Tadpoles show microhabitat partitioning within the stream, with the greatest diversity of stages in slow-flowing rocky areas. The more robust stages possessing sucker discs exploit rocky-rapids, while metamorphic stages inhabit stream margins. We use DNA-barcoding to show the existence of two disparate toad populations. Distribution modeling with forest-cover layers added, predict a very small remaining area of suitable habitats. Conservation of this climatically and ecologically restricted species hinge largely on the preservation of high-elevation primary and riparian forests and unpolluted torrents.
Figure 1: Amplexus and mating aggregations in Adenomus kandianus. (a) An amplexed pair out of water, showing axillary amplexus. (b–d) A large mating aggregation in slow water, sandy-bottomed refuge in a stream bordering the Peak Wilderness sanctuary.
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
• Pseudophilautus diversification, begins during Oligocene (31 MYA)
• A stately pace of lineage accumulation despite orogeny and climate change.
• Assemblages in most regions comprise of species arising from diverse clades.
• MRCA of a back-migrating clade to India (8.8 MYA), reconstructs as a lowland form.
• Island’s mountains serve as species pumps and refuges for Pseudophilautus evolution.
Abstract
Pseudophilautus comprises an endemic diversification predominantly associated with the wet tropical regions of Sri Lanka that provides an opportunity to examine the effects of geography and historical climate change on diversification. Using a time-calibrated multi-gene phylogeny, we analyze the tempo of diversification in the context of past climate and geography to identify historical drivers of current patterns of diversity and distribution. Molecular dating suggests that the diversification was seeded by migration across a land-bridge connection from India during a period of climatic cooling and drying, the Oi-1 glacial maximum around the Eocene-Oligocene boundary. Lineage-through-time plots suggest a gradual and constant rate of diversification, beginning in the Oligocene and extending through the late Miocene and early Pliocene with a slight burst in the Pleistocene. There is no indication of an early-burst phase of diversification characteristic of many adaptive radiations, nor were there bursts of diversification associated with favorable climate shifts such as the intensification of monsoons. However, a late Miocene (8.8 MYA) back-migration to India occurred following the establishment of the monsoon. The back migration, however, did not trigger a diversification in India similar to that manifest in Sri Lanka, likely due to occupation of available habitat, and consequent lack of ecological opportunity, by the earlier radiation of a sister lineage of frogs (Raorchestes) with similar ecology. Phylogenetic area reconstructions show a pattern of sister species distributed across adjacent mountain ranges or from different parts of large montane regions, highlighting the importance of isolation and allopatric speciation. Hence, local species communities are composed of species from disparate clades that, in most cases, have been assembled through migration rather than in situ speciation. Lowland lineages are derived from montane lineages. Thus, the hills of Sri Lanka acted as species pumps as well as refuges throughout the 31 million years of evolution, highlighting the importance of tropical montane regions for both the generation and maintenance of biodiversity.
Madhava Meegaskumbura, Gayani Senevirathne, Kelum Manamendra-Arachchi, Rohan Pethiyagoda, James Hanken and Christopher J. Schneider. 2019. Diversification of Shrub Frogs (Rhacophoridae, Pseudophilautus) in Sri Lanka – Timing and Geographic context. Molecular Phylogenetics and Evolution. In Press. DOI: 10.1016/j.ympev.2018.11.004
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
A recent (2013) taxonomic review of the freshwater-fish genus Rasboroides, which is endemic to Sri Lanka, showed it to comprise four species: R. vaterifloris, R. nigromarginatus, R. pallidus and R. rohani. Here, using an integrative-taxonomic analysis of morphometry, meristics and mitochondrial DNA sequences of cytochrome b (cytb) and cytochrome oxidase subunit 1 (coi), we show that R. nigromarginatus is a synonym of R. vaterifloris, and that R. rohani is a synonym of R. pallidus. The creation and recognition of unnecessary taxa (‘taxonomic inflation’) was in this case a result of selective sampling confounded by a disregard of allometry. The population referred to R. rohani in the Walawe river basin represents an undocumented trans-basin translocation of R. pallidus, and a translocation into the Mahaweli river of R. vaterifloris, documented to have occurred ca 1980, in fact involves R. pallidus. A shared haplotype suggests the latter introduction was likely made from the Bentara river basin and not from the Kelani, as claimed. To stabilize the taxonomy of these fishes, the two valid species, R. vaterifloris and R. pallidus, are diagnosed and redescribed, and their distributions delineated. We draw attention to the wasteful diversion of conservation resources to populations resulting from undocumented translocations and to taxa resulting from taxonomic inflation. We argue against translocations except where mandated by a conservation emergency, and even then, only when supported by accurate documentation.
Figure 4: Live color pattern variation in A–D, Rasboroides vaterifloris; E–J,R. pallidus. (A) topotypes of R. vaterifloris, Kalu basin, Gilimale; (B–D) topotypes of population identified as R. nigromarginatus by Batuwita, De Silva & Edirisinghe (2013), Kalu basin, Athwelthota; (E) Bentara basin, Pitigala; (F) topotypes of population identified as R. rohani by Batuwita, De Silva & Edirisinghe (2013), Walawe basin, Suriyakanda; (G) Bentara basin, Yagirala; (H) Gin basin, Udugama; (I) Bentara basin, Yagirala; (J) Bentara basin, Pitigala. (A, B, D, E, F, G, H) males; (C, I, J) females. Specimens not collected.
Live color pattern variation in Rasboroides vaterifloris. (A) topotypes of R. vaterifloris, Kalu basin, Gilimale; (B–D) topotypes of population identified as R. nigromarginatus by Batuwita, De Silva & Edirisinghe (2013), Kalu basin, Athwelthota.
(A, B, D) males; (C) females. Specimens not collected.
Rasboroides vaterifloris Deraniyagala, 1930
Rasbora vaterifloris Deraniyagala, 1930: 129
Rasbora nigromarginata Meinken, 1957: 65–68
Rasbora vaterifloris var. nigromarginatus Deraniyagala, 1958: 137
Rasboroides nigromarginatus (Meinken, 1957): Batuwita, De Silva & Edirisinghe, 2013
Diagnosis. Males of Rasboroides vaterifloris can be distinguished from males of R. pallidus by having the unbranched rays of dorsal, anal, pectoral and pelvic fins black along their entire length, more distinctly evident in the last unbranched ray of the dorsal fin (vs. the mentioned rays being the same color as other rays; in preserved specimens, interradial membranes of dorsal, anal, pelvic and pectoral fins with distinct, scattered melanophores (vs. absent or vaguely present only around the beginning). Females of R. vaterifloris have a lesser body depth (27.2–31.9% SL vs. 31.7–35.5) than those of R. pallidus.
Live color pattern variation in Rasboroides pallidus. (E) Bentara basin, Pitigala; (F) topotypes of population identified as R. rohani by Batuwita, De Silva & Edirisinghe (2013), Walawe basin, Suriyakanda; (G) Bentara basin, Yagirala; (H) Gin basin, Udugama; (I) Bentara basin, Yagirala; (J) Bentara basin, Pitigala.
Rasboroides rohani Batuwita, De Silva & Edirisinghe, 2013
Diagnosis. The males of Rasboroides pallidus can be distinguished from the males of R. vaterifloris by having the unbranched rays of dorsal, anal, pectoral and pelvic fins the same color as other branched rays (vs. black along their entire length); in preserved specimens, interradial membranes of dorsal, anal, pelvic and pectoral fins without distinct scattered melanophores throughout or with only minute, vague melanophores only around the beginning (vs. melanophores distinctly present). The females of R. pallidus have greater body depth (31.7–35.5% SL vs. 27.2–31.9) than females of R. vaterifloris.
Conclusion:
As a freshwater-fish genus endemic to Sri Lanka and restricted largely to streams draining the island’s dwindling rainforest estate, Rasboroides attracts considerable conservation attention. The National Red List (MOE, 2012) treats ‘R. nigromarginatus’ as Critically Endangered and R. vaterifloris as Endangered. The synonymy of these two nominal species demonstrated here allows their ranges to be combined, widening their extent of occurrence and area of occupancy and hence potentially lowering the threat-status of R. vaterifloris. Although ‘R. rohani’ has not as yet been assessed for conservation purposes, its restriction to a small population at a single locality would almost certainly have caused it to be ranked as Critically Endangered. Given that we show here that it represents only an undocumented translocation of R. pallidus, its population is now only of marginal conservation concern. Indeed, of the two valid species of Rasboroides, R. pallidus enjoys the wider range and hence warrants less conservation concern, especially given its successful translocation to two river basins (Mahaweli and Walawe) in which it did not previously occur.
In describing ‘R. rohani’ as a new species, Batuwita, De Silva & Edirisinghe (2013) were misled by apparently collecting only the largest specimens for their sample while neglecting to account for allometric growth. It is additionally regrettable that the type series of ‘R. rohani’ designated by these authors cannot be identified in the collection of the National Museum of Sri Lanka, in which it was stated to be deposited.
Both translocations referred to in this paper were made by well-meaning citizens but without the safeguards that should apply in such cases. Perhaps most egregiously, no records were published of the rationale for translocation or the precise identity and origin of the source population. We urge that any future attempts to introduce species to novel habitats be guided by IUCN/SSC (2013) and that the intentional release or introduction of species without legal sanction be prohibited in Sri Lanka.
Hiranya Sudasinghe, Jayampathi Herath, Rohan Pethiyagoda and Madhava Meegaskumbura. 2018. Undocumented Translocations Spawn Taxonomic Inflation in Sri Lankan Fire Rasboras (Actinopterygii, Cyprinidae). PeerJ. 6:e6084. DOI: 10.7717/peerj.6084
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
