Guwahati: It has a remarkable ability to mimic bird droppings. Arachnologists from Assam have discovered the bird dung crab spider (Phrynarachne decipiens) for the first time in India while studying crab spider specimens from two locations: Sonapur in Kamrup (Metropolitan) district and the Chirang Reserve Forest in Kokrajhar district.
The finding, published in a recent scientific paper, adds to the known species within the genus Phrynarachne, originally established by the renowned arachnologist Tamerlan Thorell in 1869. The research team included Sangeeta Das, Jatin Kalita, Nilutpal Mahanta, Dulur Brahma, and Paris Basumatary.
“This type of camouflage, known as aggressive mimicry, is rare and highly specialized. By resembling something as unappealing as bird excreta, the spider effectively avoids predators and, in some cases, may even lure prey. This strategy represents an advanced form of survival adaptation that is fascinating to biologists and ecologists,” one of the researchers associated with the discovery said.
“Previously, this spider was only recorded in regions like Indonesia and Malaysia. Finding it in a new location highlights the vast and largely unexplored biodiversity in areas like Assam, opening up new avenues for ecological and biogeographical studies,” the researcher added.
Phrynarachne decipiens was originally described based on a female specimen from Indonesia. The last description of this species was made by Jacobson in 1921 with only a sketch of its habitus. Since its original description, there have been no detailed illustrations of the species. Only 10 species within this genus have been studied after their original descriptions. The current paper aims to re-describe P. decipiens and reports its first occurrence in Assam, India.
The genus Phrynarachne now comprises 35 recognized species, with only three previously reported from India. The species P. ceylonica, P. peeliana, and P. tuberosa have long been documented in the subcontinent. The addition of P. decipiens, first described from Indonesia by Forbes in 1884, enriches the biodiversity records of the region.
The team re-described P. decipiens, focusing on its unique morphological traits. Notably, the species can be distinguished from its close relative P. peeliana by its stout spermatheca and short copulatory ducts.
“The chalky white coloration and distinctive markings of P. decipiens help it mimic bird droppings, a camouflage strategy that makes it nearly invisible to predators,” another researcher said.
“The morphological characteristics of the specimens closely match those described in historical records, providing strong evidence for the species’ identity,” the researchers noted.
The researchers say the discovery not only expands the known distribution of P. decipiens but also underscores the rich and largely unexplored biodiversity of Assam’s forests.
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