A New Species of Chigger (Acari: Trombiculidae) from Indonesia and Current Differentiation of Trombicula Berlese, 1905 Sensu Stricto Group.

Background: Two new species of chiggers in the two genera (Chiroptella Vercammen-Grandjean, 1960 and Rudnicula Vercammen-Grandjean, 1964) have been described in Indonesia since 2020. The checklist of all known bat-infesting chiggers has also been compiled for Indonesia. It summarizes 16 species in 9 genera of chiggers parasitizing 12 bat species belonging to 5 families collected on 8 Indonesian islands. Nine specimens collected in 2020 on Nusa Penida Island were not included in the checklist because of their uncertain taxonomy. In the current paper, we resolve the taxonomy of these specimens belonging to Trombicula sensu stricto group. We also revise the existing characters of this group and provide new characters helping with the clear definition of this taxa.

Methods: Hosts and chiggers were captured in February 2020 in Nusa Penida Islands in Indonesia using standard bat-capturing and parasite-collecting methods. For the specimens examined in this study were provided drawings, measurements, and microscopy images. This type material is deposited in the Slovak and Czech National museums.

Results: In the paper, we describe a new species parasitizing diadem leaf-nosed bat in the Goa Peteng cave on Nusa Penida Island (Lesser Sunda Islands, East Indonesia). This new species differs from all related species by the presence of a very long tarsala I (S). A key to the larvae of all seven known Trombicula s. s. species is provided. The differentiation of Trombicula s. s. group is based on leg segmentation fsp = 6.6.6, rugose scutum with complete AM, AL and PL setation, and fT = 5B, 5BN or 4B2N.

Conclusion: A new species within the genus Trombicula, group minor has been described. The new species also increases the number of known chiggers in Indonesia and the number of species parasitizing the host species Hipposideros diadema. Trombicula s. s. has also been revised and more clearly defined.