Non-biting midge (Diptera: Chironomidae) diversity in the University of the Philippines Diliman, Quezon City including the description and DNA barcoding of a new species Kiefferulus dilimanensis sp. nov. and four new records

Urban biodiversity studies often emphasize disease vectors and economically important insects, leaving ecologically significant groups underexplored. In the Philippines, urban development has degraded aquatic systems, with biomonitoring revealing pollution-tolerant taxa. The family Chironomidae Newman, 1834, among the most pollution-tolerant aquatic insects, remains taxonomically understudied in tropical Asia. This study surveyed Chironomidae in the University of the Philippines Diliman, one of the remaining green spaces in Metro Manila. One new species, Kiefferulus dilimanensis sp. nov., and four new records, K. calligaster (Kieffer, 1911), Chironomus circumdatus (Kieffer, 1916), C. crassiforceps Kieffer, 1916, and C. flaviplumus Tokunaga, 1940, were identified. Diagnostic traits, particularly of the male hypopygium, were illustrated and incorporated into a local dichotomous key. Mitochondrial COI (mtCOI) (658 bp) analysis supported morphological delineations: K. dilimanensis sp. nov. formed a distinct clade (bootstrap = 99) with 9.00–9.43% K2P divergence from K. tainanus (Kieffer, 1912) and K. barbatitarsis (Kieffer, 1911), exceeding typical intraspecific thresholds (<3%). Philippine K. calligaster clustered with Asian conspecifics (1.49–2.83% divergence), while C. circumdatus and C. flaviplumus (Type C) showed low divergences (≤1.12%), confirming conspecificity. C. crassiforceps exhibited higher divergence (3.02–7.40%), suggesting cryptic diversity. This study provides the first COI barcodes for Philippine Chironomidae and underscores the role of integrative taxonomy in revealing hidden biodiversity within tropical urban ecosystems.