The genital area of Halacaridae (Acari), life stages and development of morphological characters and implication on the classification Author Bartsch, Ilse text Zootaxa 2015 3919 2 201 259 journal article 10.11646/zootaxa.3919.2.1 8a0f71e3-5416-41c5-8e7d-b4cc574b7340 1175-5326 245246 8CB77F9E-A35E-43E2-91F7-7822AE421B33 Thalassacarus Newell, 1949 Type species. Thalassacarus commatops Newell, 1949 . Adults. In female and male GP and AP fused. Female GA with three pairs of slender pgs; sgs lacking. Female with three pairs of internal gac arranged in line and extending anteriad slightly beyond middle of GO ( Newell 1949: fig. 4 ). Length of ovipositor and number and size of genital spines not described. Male GA with about 25 pairs of slender pgs and four pairs of sgs ( Newell 1949: fig. 3 ). Male GO smaller and distance to anal cone larger than in female. GO with three pairs of internal gac. No epimeral pores mentioned in the description. Juveniles. Only one nymphal stage seen, supposedly the deutonymph. GP separated from AP; GP with two pairs of internal gac and two pairs of pgs; sgs not mentioned in the description but obviously present ( Newell 1949: fig. 10 ). Further juvenile stages and larva unknown. Remarks. The single species at present found is spread along the Pacific coast of the United States of America ( Newell 1949 ).