Police in Madagascar have arrested two men attempting to smuggle out nearly 200 threatened tortoises, including two dozen of the rarest species on Earth, a conservation group said Thursday. The 26 specimens of Ploughshare tortoise (Astrochelys yniphora) seized comprise about five percent of the estimated surviving wild population of the critically endangered animal, native to northern Madagascar. Authorities found the live tortoises in a box and three bags on the tarmac at Antananarivo\'s Ivato Airport, according to TRAFFIC, which monitors illegal trade in wildlife. The contraband was minutes from being loaded on a plane, and was destined -- after transfers in Nairobi and Dubai -- for Jakarta, Indonesia, police reportedly said. \"In the case of rare, high value species like these, they would certainly have been destined for the pet trade in Asia,\" Richard Thomas of TRAFFIC said of the Ploughshare tortoises. Border police also found 169 Radiated tortoises (Asstrochelys radiata) and one Spider tortoise (Pyxis arachnoides), prized by collectors internationally. All three species are classified as critically endangered on the International Union for the Conservation of Nature (IUCN) Red List, the benchmark reference for the conservation status of wildlife. International trade in the species -- which are also protected under national law in Madagascar -- is illegal, but seizures are not uncommon in markets in Southeast Asia. A recent investigation by TRAFFIC, which is funded jointly by the IUCN and WWF, found all three species in markets in Thailand, more than 150 specimens in all. \"Responsibility does not lie with Madagascar alone, but also with importing countries,\" said Chris Shepherd, TRAFFIC\'s regional deputy director for Souteast Asia. \"Authorities in Indonesia and other parts of Southeast Asia should take firm and immediate action against those trading in these species and put an end to this illicit trade.\" The wild population of Ploughshares, which grow to 40 centimetres (16 inches) and up to 10 kilos (22 pounds), has dwindled rapidly in recent decades, and is estimated at 440 to 700 individuals. Historically eaten locally as a delicacy, its habitat has been drastically reduced by agricultural practices, especially the burning of fields. The main threat today is poaching for the illegal pet trade, according to the IUCN. The species is now restricted to five small, isolated sub-populations, and could have as few as 200 remaining adults that can reproduce.