From legacy taxonomic records to faunal inference: Sarcophagidae (Diptera) richness and distributional patterns in the lakes region of Türkiye

Background Legacy natural-history collections can provide auditable faunal baselines, but the biodiversity patterns they contain may also reflect uneven collecting histories. Using taxonomically verified Sarcophagidae from the Lakes Region of southwestern Türkiye, we integrated voucher linkage, taxonomic and spatial harmonization, reconstruction of sampling history, and sensitivity analysis to determine what the collection documents, quantify how temporal sampling replication relates to recorded richness, and interpret associated faunal patterns within that sampling framework. Results The collection comprised 202 occurrence records and 300 preserved voucher specimens from 73 source-defined sampling locations and 57 canonical locality units across four provinces (Afyonkarahisar, Antalya, Burdur, and Isparta). Of these, 201 occurrences and 299 vouchers were identified to species, representing 37 species at 72 locations. Sampling was highly uneven: 80.7% of collection occurrences and 85.3% of specimens were collected in 2014–2015, and 58 of the 73 source locations had only one documented sampling date. Across the 72 locations represented by species-level identifications, richness was positively associated with unique sampling dates (Spearman ρ = 0.610, 95% bootstrap CI = 0.451–0.748, n = 72, p = 1.26 × 10⁻⁸). The association persisted after excluding the most intensively sampled location (ρ = 0.585) and within 2014–2015 (ρ = 0.514), but weakened after excluding Isparta (ρ = 0.253, p = 0.222), where repeated sampling was concentrated. Palaearctic and West Palaearctic elements comprised 22 of 37 species (59.5%). At the four-province study-area scale, 25 of the 37 species had no earlier qualifying published record from any focal province; at the province scale, 49 of 52 species × province combinations constitute first published provincial records. None were new to Türkiye. Four unranked resampling classes placed 52 of 72 species-level locations (72.2%) in Class A (broad resurvey), five each (6.9%) in Classes B (repeatability resurvey) and C (verification resurvey), and 10 (13.9%) in Class D (legacy comparison locations). Conclusions The collection provides a defensible, voucher-based baseline of the documented Sarcophagidae fauna while showing that recorded richness must be interpreted alongside an uneven history of temporal replication. The spatial, elevational, chorological, and provincial patterns recovered from the collection are meaningful features of the verified record, but not standardized estimates of underlying richness. By preserving the specimen-to-record evidence chain and making sampling structure explicit, the study converts heterogeneous legacy material into both an auditable zoological baseline and a practical framework for targeted, standardized resampling.