ZIP code matters: Nicsmirnovius paggii, a new species from fitzpatriki-complex (Cladocera: Chydoridae) does not co-occur with Nicsmirnovius incredibilis

The literature indicates that Nicsmirnovius fitzpatricki represents a species complex and that populations outside the type region (Florida, USA) may represent other taxa. As a result of the comparison of South American populations to the original N. fitzpatricki redescription, we described Nicsmirnovius paggii sp. nov.. Species separation was supported by limb characters, especially by the presence of a sensillum in endite 3 of the first limb, in the armature of the gnathobase of the second and fifth limbs, and in the setae of the distal endite of the third limb. Body shape, postabdomen, antenna and antennules are similar to N. fitzpatricki, whichmakes it difficult to correctly distinguish these species based exclusively on external characters. The male is also described, and this is the second time a male of this genus has had its morphology studied. Ecological aspects also differ from another Nicsmirnovius species, since the occurrence of N. paggii sp. nov. is not associated with bottom sediments. Lastly, the morphology of N. paggii sp. nov. was shown to be very different from the Amazonian Nicsmirnovius incredibilis. After redescription, we concluded that N. incredibilis is a specialized species endemic to the middle and lower portion of the Amazonas River Basin.