Eresus cinnaberinus

Eresus cinnaberinus and Eresus niger are names formerly used for a group of spiders in the genus Eresus now divided into three species, E. kollari, E. sandaliatus, and E. moravicus.

The three species differ in size, colour pattern, shape of prosoma and copulatory organs, and habitat, with no morphologically intermediate forms.

As eastern and western E. kollari are genetically different, with the eastern form likely a hybrid between "pure" E. kollari and E. moravicus, it is possible that later revisions will partition it into additional species.

[1] Both E. cinnaberinus and E. niger are now regarded as nomina dubia.

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