A new species of Trachygamasus from Poland, a new definition of the genus, and a key to the world species (Parasitiformes: Parasitidae) Author Witaliński, Wojciech text Zootaxa 2017 4303 3 407 416 journal article 32516 10.11646/zootaxa.4303.3.6 4bb0d59c-be0e-441e-9819-3eb381c46808 1175-5326 841257 E36DA2B0-A0E3-427F-B101-B3833CBB077E Key to adults of Trachygamasus species Females 1. Central prong of gnathotectum distally widened and bifid or trifid apically........................................ 2 - Central prong of gnathotectum acuminate.................................................................. 6 2. All dorsal setae simple, seta al on palpfemur bifid....................................... T . macfarlanei Costa, 1962 - Some dorsal setae pilose, seta al on palpfemur spatulate.......................................................3 3. Dorsal setae j1 feathered............................................................ T . fallax Holzmann, 1969 - Dorsal setae j1 simple..................................................................................4 4. Opisthonotum with 21 pairs of setae; length to width of opisthonotum ca . 7/12 (0.6)............. T . biplumatus Karg, 1998 - Opisthonotum with 14–18 pairs of setae; length to width of opisthonotum 4/5 to 2/3 (0.7–0.8).........................5 5. Length of idiosoma exceeding 600 µm, opisthonotum bears 15–18 pairs of setae, endogynium ovate in outline, composed of two circular parts fused axially and forming a figure 8.............................. T . ambulacralis ( Willmann, 1949 ) - Length of idiosoma less than 500 µm, opisthonotum bears 14 pairs of setae, endogynium mushroom-shaped in outline, com- posed of two circular parts as in T . ambulacralis ......... T . gracilis ( Karg, 1965 ) (= T . minor Holzmann, 1969 . Karg, 1971 ) 6. Epigynium regular (equilateral) triangle with straight lateral sides; gnathotectum central prong narrow, similar to lateral ones7 - Epigynium with arcuate lateral sides, central prong of gnathotectum broader and more solid than lateral prongs...........8 7. Sternal setae st2 simple and thin, distance between st2 greater than between st1 . Opisthogaster with 7 pairs of setae, length of idiosoma 670–700 µm.......................................................... T . medianus Tichomirov, 1977 - Sternal setae st2 stout, distance between st2 smaller than between st1 . Opisthogaster with 8 pairs of setae, length of idiosoma ca . 560 µm........................................................................ T . triangulus Karg, 1978 8. Sternal setae st2 simple, similar to st1, distance between st2 greater than between st1 and st3 . Epigynium width greater than length........................................................................... T . pusillus ( Berlese, 1892 ) - Sternal setae st2 shorter and thicker than st1 . Endogynium hyaline, elongated axially................................9 9. Endogynium narrow, tubular, with separate elliptic anterior part, ca . 90 µm long, extending nearly along the entire length of the epigynium.................................................................... T . borealis Ma & Wang, 1996 - Endogynium cross-shaped, ca . 58 µm long, its length not exceeding half of the length of the epigynium.... T . gerdi sp. nov.