Studying predation on rare aquatic taxa is difficult particularly when dealing with legally protected, large predatory species. Moreover, observing predation on species found in low numbers is difficult in remote, turbid rivers, particularly where the species is nocturnal (Gleiss et al. 2017). Fig. 1, showing an Australian freshwater crocodile (Crocodylus johnstoni) preying upon a freshwater sawfish (Pristis pristis), represents a rare example with considerable implications for conservation.
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David L. Morgan, Ruchira Somaweera, Adrian C. Gleiss, Stephen J. Beatty and Jeff M. Whitty. 2017. An Upstream Migration Fought with Danger: Freshwater Sawfish Fending Off Sharks and Crocodiles. Ecology - The Scientific Naturalist. in press 0(0); 1–3. DOI: 10.1002/ecy.1737
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.
We present new records of occurrence of Schneider’s Dwarf Caiman, Paleosuchus trigonatus and extend its geographical distribution. Eight individuals were caught in the following locations: Sangue River, in the municipality of Campo Novo dos Parecis, Claro River and Marapi River, in the municipality of São José do Rio Claro, and tributaries of the Juruena River, in the state of Mato Grosso, Brazil. These records extend the geographical distribution of the species nearly 500 km south of the limit given in published range maps.
Keywords: New records; conservation; Paleosuchus; Mato Grosso; Brazilian Amazon
Figure 1. Male specimen of Paleosuchus trigonatus captured in Claro River, showing some diagnostic characters. A. General view of the body. B. Head shape. C. Arrow indicates the two scales of the sacral region. D. Post-occipital region.
Figure 3. New records of the geographic distribution of Paleosuchus trigonatus in the Sangue, Claro, Marapi and Alegre rivers in the Cerrado biome, Mato Grosso, Brazil. Triangle = 8 individuals captured; inverted triangle = 3 individuals observed and not captured.
Zilca Campos, Fábio Muniz and William E Magnusson. 2017. Extension of the Geographical Distribution of Schneider’s Dwarf Caiman, Paleosuchus trigonatus (Schneider, 1801) (Crocodylia: Alligatoridae), in the Amazon–Cerrado Transition, Brazil. Check List. 13(4); 91-94. DOI: 10.15560/13.4.91
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.
Molecular and morphological evidence has shown that the African slender-snouted, or sharp-nosed, crocodile Mecistops cataphractus (Cuvier, 1824) is comprised of two superficially cryptic species: one endemic to West Africa and the other endemic to Central Africa. Our ability to characterize the two species is compromised by the complicated taxonomic history of the lineage and overlapping ranges of variation in distinguishing morphological features. The name M. cataphractus was evidently originally based on West African material, but the holotype is now lost. Although types exist for other names based on the West African form, the name M. cataphractus is sufficiently entrenched in the literature, and other names sufficiently obscure, to justify retypification. Here, we designate a neotype for M. cataphractus and restrict it to West Africa. We resurrect M. leptorhynchus as a valid species from Central Africa and identify exemplary referred specimens that, collectively, overcome the obscurity and diagnostic limits of the extant holotype. We additionally indicate suitable neotype material in the event the holotype is lost, destroyed, or otherwise needing replacement, and we rectify the previously erroneous type locality designation. We provide a revised diagnosis for crown Mecistops, and revise and update previous descriptions of the two living species, including providing both more complete descriptions and discussion of diagnostic characters. Finally, we provide considerable discussion of the current state of knowledge of these species’ ecology, natural history, and distribution.
Etymology. Gray (1844) did not offer an etymology for Mecistops. However, ‘Mecist’ is most likely derived from the Greek mekist, meaning longest, and ‘ops’ is a derivative of the Greek opsis meaning appearance or aspect. Thus, the name Mecistops most likely refers to the elongated appearance of the skull/snout in slender-snouted crocodiles relative to species of the genus Crocodylus.
Content. Mecistops cataphractus (Cuvier, 1824) and M. leptorhynchus (Bennett, 1835).
Distribution. Mecistops is endemic to western Africa ranging from Lake Tanganyika and Lake Mweru in the east to the Gambia River in the west and, at least historically, occupying all major river drainages, lakes, and wetlands with appropriate habitat north to the 13th parallel in far western Africa (i.e., Senegambia region), the 10th parallel in West Africa (i.e., Upper Guinea block), and the 6th parallel in Central Africa (Fig. 1).
Map showing the distribution of Mecistops and its two content species: M. cataphractus and M. leptorhynchus.
Mecistops cataphractus (Cuvier, 1824) typically colored and patterned animals from the Senegambia area illustrating the dark gold background color and heavy black blotching, jaw spots, and overall dark patterning from the Gambia River, River Gambia National Park, The Gambia.
Etymology. Cuvier (1824) did not provide an etymology for cataphractus. However, we assume it came from the Greek kataphraktos (κατάφρακτος) meaning armored, shielded or completely enclosed. Cuvier (1824) gave this species the French common name “crocodile à nuque cuirassée” (“armor-necked crocodile”). Both the Latin and French are presumably in reference to the extra rows of dorsal scutes joining the nuchal cluster compared to other crocodiles of the genus Crocodylus.
Mecistops leptorhynchus, high orange and black individual from the N’gowe River, Gabon.
(photo: J. Thorbjarnarson)
Mecistops leptorhynchus (Bennett, 1835)
Crocodilus leptorhynchus Bennett, 1835: 128 (apud. Fernando Po; Type NHMUK 1947.3.6.35, juvenile, Cuvier 1836: 116). Murray 1862: 222.
Etymology. Bennett (1835) did not provide an etymology for leptorhynchus. However, ‘lepto’ is derived from the Greek leptós meaning thin, fine, or slender and rhynchos meaning beak or snout. Thus, Mecistops leptorhynchus is a slender snouted crocodylian of the genus Mecistops, which Bennett may have found appropriate given his finding of a longer head length to head width ratio (3:1) than he found in M. cataphractus (2.5:1).
Conclusions
As for other recently proposed taxonomic revisions within Crocodylia (i.e., the dwarf and Nile crocodile cryptic species complexes), at first glance slender-snouted crocodiles from Lake Tanganyika to the Gambia River appear quite similar. However, we here provide significant cranial shape, external phenotypic, and ecological data that, in addition to previously published molecular and discrete morphological evidence (Shirley et al. 2014), strongly support the recognition of two species in the genus Mecistops. That all morphological, molecular, and ecologically segregating characters are isolated in two different biogeographic zones makes identification of M. cataphractus and M. leptorhynchus, at least in the wild, a non-contentious issue. Further, for legislation enforcement (e.g., CITES), as well as management of captive populations, we identified sufficient molecular and morphological characters for unambiguous species identification. However, this may not be so critical for the former as Mecistops species are integrally protected and listed in CITES Appendix I in all range states and are generally not considered of value in the international trade of crocodylian products (e.g., skins).
Matthew H. Shirley, Amanda N. Carr, Jennifer H. Nestler, Kent A. Vliet and Christopher A. Brochu. 2018. Systematic Revision of the Living African Slender-snouted Crocodiles (Mecistops Gray, 1844). Zootaxa. 4504(2); 151–193. DOI: 10.11646/zootaxa.4504.2.1
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.
