First report on mermithid parasitism (Enoplea: Mermithidae) in a Southeast Asian spider (Araneae: Araneidae).

Details­ about­ the­ record­ of­ a­ juvenile­ mermithid­ roundworm­ parasitizing­ the­ bark­ spider­ Caerostris sumatrana Strand,­ 1915­ from­ Thailand­ are­ presented.­ The­ morphology­ and­ ecology­ of­ both­ organisms­ is­ discussed.­ Morphological features­ suggest­ this­ juvenile­ nematode­ belongs­ to­ the­ genus­ cf.­ Aranimermis.­ Due­ to­ the­ subadult­ stage­ of­ parasite,­ identifi­cation­ to­ species-level­ was­ not­ possible.­ This­ fi­rst­ report­ of­ a­ nematode­ infection­ in­ C. sumatrana­ with­ several­ recent­ fi­ndings­ from­ other­ studies­ signifi­cantly­ adds­ to­ the­ current­ inventory­ of­ mermithids­ parasitizing­ spiders. Moreover,­ our­ fi­nding­ is­ among­ the­ fi­rst­ record­ of­ this­ host-parasite­ interaction­ from­ Southeast­ Asia.