The Complete Mitochondrial Genome of endemic giant tarantula, Lyrognathus crotalus (Araneae: Theraphosidae) and comparative analysis

Abstract

Rajasree chakraborty, priya prasad, Shantanu Kundu, inderjeet tyagi & Kailash chandra the complete mitochondrial genome of Lyrognathus crotalus is sequenced, annotated and compared with other spider mitogenomes. It is 13,865 bp long and featured by 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs), 13 protein-coding genes (PCGs), and a control region (CR). Most of the pcGs used Atn start codon except cox3, and nad4 with ttG. comparative studies indicated the use of ttG, ttA, ttt, GtG, ctG, ctA as start codons by few pcGs. Most of the tRnAs were truncated and do not fold into the typical cloverleaf structure. further, the motif (cAtAtA) was detected in cR of nine species including L. crotalus. the gene arrangement of L. crotalus compared with ancestral arthropod showed the transposition of five tRNAs and one tandem duplication random loss (TDRL) event. Five plesiomophic gene blocks (A-E) were identified, of which, four (A, B, D, E) retained in all taxa except family Salticidae. However, block c was retained in Mygalomorphae and two families of Araneomorphae (Hypochilidae and Pholcidae). Out of 146 derived gene boundaries in all taxa, 15 synapomorphic gene boundaries were identified. TreeREx analysis also revealed the transposition of trnI, which makes three derived boundaries and congruent with the result of the gene boundary mapping. Maximum likelihood and Bayesian inference showed similar topologies and congruent with morphology, and previously reported multi-gene phylogeny. However, the Gene-Order based phylogeny showed sister relationship of L. crotalus with two Araneomorphae family members (Hypochilidae and pholcidae) and other Mygalomorphae species. The order Araneae is classified into two infra-orders Mesothelae (primitive spiders) and Opisthothelae (modern spiders). The infra-order Opisthothelae is further classified into two suborders Mygalomorphae and Araneomorphae with 117 families. The family Theraphosidae belongs to suborder Mygalomorphae of infra-order Opisthothelae with 992 species. Out of 992 species, 52 species are known from India 1. The members of family Theraphosidae are commonly known as tarantulas or giant spiders for their huge body size. These giant spiders play an important role in controlling the insects 2 and also predators on vertebrates and invertebrates 3. The venom of these tarantulas is the main source of pharmacological research 3. The Pet trade of tarantulas across the globe is in great demand due to their body size, attractiveness, longitivity and for economic point of view 4. So far, 13 species in three genera (Poecilotheria, Thrigmopoeus and Lyrognathus) from India have been reported in the pet trade 4. The species Lyrognathus crotalus is endemic to India restricted to northeast region and frequently traded. The correct identification of these tarantulas is the basic need due to their economical and medicinal values and involvement in the pet trade. However, identification of species in the absence of well-preserved specimens is not possible through morphology ...

The complete mitochondrial genome of the intertidal spider (Desis jiaxiangi) provides novel insights into the adaptive evolution of the mitogenome and the evolution of spiders

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Complete Mitochondrial Genome of Phoneutria Boliviensis (Araneae, Ctenidae): New Insights Into the Phylogeny and Evolution of Spider

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