Hoplobatrachus litoralis
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Hoplobatrachus litoralis |
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| Hasan , Kuramoto , Islam , Alam , Khan & Sumida , 2012 |
Hoplobatrachus litoralis is a frog through the family Dicroglossidae . It was only described in 2012and is common in the southeast coastal regions of Bangladesh and in southern and central parts of Myanmar .
description
Hoplobatrachus litoralis is a large frog with a head-trunk length of 81 to 102 millimeters in adult males and 83 to 121 millimeters in adult females. Specimens preserved in alcohol are dark gray dorsally and on the outside of the limbs with numerous large black spots that become smaller towards the flanks. A continuous thin, light line runs from the tip of the snout to the end of the body, which is occasionally missing. The ventral side is uniformly whitish or yellowish gray, with the exception of a few dark spots along the edge of the lower jaw. The lively color varies in the dorsal basic color between yellowish brown and dark brown with dark brown to black markings. The ventral side is creamy white and the narrow back stripe is creamy white to yellowish white. The eardrum is dark gray with a small light ring in the center. Male frogs have a pronounced oestrus at the base of the first finger and a vocal sac under each corner of the mouth, which is gray in color in preserved specimens.
Hoplobatrachus litoralis can be distinguished from the very similar species Hoplobatrachus tigerinus by the mitochondrial DNA and morphologically by broad black bands that run from the eyes over the nostrils to the front edge of the upper jaw without touching each other. Another black band runs along the edge of the upper jaw, and the interpupillary distance is smaller relative to the distance between the nostrils and the width of the eyelids. On the inner upper arm of H. litoralis there is a distinct black stripe, which is missing in H. tigerinus . The inner metatarsal tubercle is black, whereas in H. tigerinus it is colorless. The males' mating calls are similar in both species, but the main frequency and number of impulses are different.
The mating calls of Hoplobatrachus litoralis occur with an average of 4.4 seconds apart. The single call has a duration of 0.28 seconds and consists of twenty sounds in rapid succession. The fundamental frequency is 0.30 kHz , the dominant frequency of 1.2 kilohertz. These bioacoustic features, in particular the lack of a second dominant frequency, clearly distinguish the individuals of H. litoralis from the Indian populations of H. tigerinus investigated by a research group with the participation of the zoologist Hans Schneider in the early 1990s . Their calls lasted 0.30 seconds with an average of 16 sounds and two dominant frequencies of 1.65 and 0.52 kilohertz (northeast India, states of Assam and Meghalaya ) or 0.22 seconds with an average of 12.6 sounds and two dominant frequency ranges of 1 , 5 to 2.2 kilohertz and 0.2 to 1.2 kilohertz (Southwest India, Karnataka ).
distribution
The type location is near the coast at five meters above sea level in the Upazila Teknaf ( 20 ° 52 ′ 0 ″ N , 92 ° 18 ′ 0 ″ E ) in the Cox's Bazar district of the Chittagong division , in the extreme southeast of Bangladesh . The first discovery sites are all situated in the district of Cox's Bazar, from a narrow coastal strip in the far southeast of Bangladesh to 500 meters high in the Chittagong Hill Tracts , and on the few kilometers off the coast in the Bay of Bengal lying island St. Martin's Iceland . Therefore, H. litoralis was initially considered to be endemic to the Cox's Bazar district, but it was always considered possible that the range extends to Myanmar . In 2014, some specimens from the Bago region and the Yangon region of Myanmar previously identified as H. tigerinus were examined for a molecular genetic investigation of the amphibian fauna of the planned Tanintharyi National Park in the south of Myanmar . They have been recognized as H. litoralis , so the range of the species extends to the center and south of Myanmar.
The preferred habitats are plant-rich ditches or pools in the river marshes at the foot of the southern Chittagong Hill Tracts. There the species lives sympatric with Hoplobatrachus crassus and several species of the genera Euphlyctis , Minervarya and Polypedates . The species Hoplobatrachus tigerinus is widespread in Bangladesh and is also found in the districts of Chittagong and Bandarban , but its range does not seem to overlap with that of Hoplobatrachus litoralis .
Way of life
Hoplobatrachus litoralis feeds on a wide variety of insects and earthworms , but also on small fish and snakes .
Hazard and protection
The World Conservation Union IUCN has Hoplobatrachus litoralis in 2015 in its Red List of Fauna of Bangladesh in the early warning list (Category - NT Near Threatened added). The classification was made because of the small known distribution area and the feared hunting because of their frog legs .
Systematics
Hoplobatrachus litoralis was described as the fifth species of the genus Hoplobatrachus , which occurs with one species in Central and West Africa and now with four species in South and Southeast Asia. Hoplobatrachus and eleven other genera with around 200 species form the subfamily Dicroglossinae, which in turn belongs to the family Dicroglossidae with another subfamily that is poor in species . Until their division in 2006, Hoplobatrachus belonged to the family Real Frogs (Ranidae).
Crossing experiments between the three species Hoplobatrachus litoralis , Hoplobatrachus tigerinus and Hoplobatrachus rugulosus showed that crossings of H. rugulosus with one of the other two species lead to sterility and severely restricted viability of the offspring. Most of the offspring die in the tadpole stage . In contrast, crosses of H. litoralis with H. tigerinus produce offspring with an only slightly increased mortality rate and almost unlimited fertility.
Initial description
The molecular genetic investigation of Bangladeshi frogs by a group of biologists led by herpetologist Mahmudul Hasan from the University of Hiroshima led to the conclusion that the frogs from Bangladesh previously identified as Hoplobatrachus tigerinus belong to two species. The newly recognized species lives in the extreme south-east of the country and can be distinguished morphologically from H. tigrinus by its mating calls and by the mitochondrial DNA . The first description of Hoplobatrachus litoralis was made in 2012 by six members of the group, including Hasan. The holotype is an adult female captured at the type site in June 2011, which is in the collection of the Institute for Amphibian Biology at the University of Hiroshima with seven paratypes, four adult female and three adult male frogs from the type site and another site in the district of Cox's Bazar . The species name litoralis is derived from the Latin litus ( coast ) and means based on the coast or living on the coast .
Web links
- Hoplobatrachus litoralis on the IUCN Red List for Bangladesh
Individual evidence
- ↑ a b c d e f g Mahmudul Hasan et al .: A new species of genus Hoplobatrachus (Anura, Dicroglossidae) from the coastal belt of Bangladesh . In: Zootaxa 2012, Volume 3312, No. 1, pp. 45-48, doi: 10.11646 / zootaxa.3312.1.2 .
- ↑ Ravishankar Dundappa Kanamadi, Channayya Rajashekar Hiremath and Hans Schneider : Vocalization and breeding period in the south Indian tropical frog Rana crassa (Jerdon) . In: Zoologischer Anzeiger 1992, Volume 228, No. 1-2, pp. 26-31, ISSN 0044-5231 .
- ^ Hassan Al-Razi: Four New Herpetofaunal Records from Saint Martin's Island, Cox's Bazar, Bangladesh . In: ICRF Reptiles & Amphibians 2017, Volume 24, No. 3, pp 162-167. Digitalisat .
- ↑ a b Md. Kamrul Hasan and Mohammed Mostafa Feeroz: Species diversity and habitat preferences of amphibian fauna in six protected areas of Bangladesh . In: Bangladesh Journal of Zoology 2014, Volume 42, No. 1, pp. 105-116, doi: 10.3329 / bjz.v42i1.23341 .
- ^ Daniel G. Mulcahy et al .: Filling the BINs of life: Report of an amphibian and reptile survey of the Tanintharyi (Tenasserim) Region of Myanmar, with DNA barcode data . In: ZooKeys 2018, Volume 757, pp. 85-152, doi: 10.3897 / zookeys.757.24453 .
- ↑ a b Rukshana Sultana: Hoplobatrachus litoralis . In: IUCN Bangladesh (ed.): Red List of Bangladesh. Volume 4. Reptiles and Amphibians . International Union for Conservation of Nature (IUCN), Bangladesh Country Office, Dhaka 2015, ISBN 978-984-34-0737-5 , p. 235.
- ↑ Mahmudul Hasan et al .: Reproductive Isolating Mechanisms in the Bangladesh Coastal Bullfrog Hoplobatrachus litoralis and Its Congeneric Species Revealed by Crossing Experiments and Examination on Spermatogenesis of the Hybrids . In: Asian Herpetological Research 2017, Volume 8, No. 1, pp. 27-38, doi: 10.16373 / j.cnki.ahr.160026 .
- ↑ Mahmudul Hasan et al .: Cryptic Anuran Biodiversity in Bangladesh Revealed by Mitochondrial 16S rRNA Gene Sequences . In: Zoological Science 2012, Volume 29, No. 3, pp. 162-172, doi: 10.2108 / zsj.29.162 .