Thamnocephalidae
Creators: name: Rogers, D. Christopher
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Branchiopoda
Anostraca
Thamnocephalidae

description: Key to Genera of Thamnocephalidae
The most recent keys to anostracan higher taxonomy are confusing and inadequate. Brtek and Mura (2000) published keys to the anostracan families and genera that did not use the standardized terminology of previous authors, used unclear and confused English, and presented limited and inaccurate diagnoses of each family and genus with numerous errors. For example, the first character in the key couplet to the Thamnocephalidae reads: “Basal part of penis soft, exceptionally (sic) with small chitinized formations on basalmost portion.” Brtek and Mura further define the Thamnocephalidae with “Usually with an odd frontal process...”
Dumont and Negrea (2002), in their book summarizing current understanding of the Branchiopoda (from a Eurocentric perspective) presented keys to the anostracan families that are far clearer than those of previous authors. However, the keys use some characters that are not exclusive to one family or another and some of the given family­level defining characters are not found in all genera within that family. For example, they state in their key that the thamnocephalid penes are only composed of a retractile portion. However the penes of Carinophallus, Dendrocephalus and most Branchinella have a rigid basal portion as do other families. Furthermore, Phallocryptus bears large spinose patches on the complex rigid basal portions of the penes.
I present here a key to the genera of the family Thamnocephalidae.
1 Cercopods broadly transverse and fused with abdomen into a broad ‘paddle’; Americas ........................................................................................ Thamnocephalus
1' Cercopods free, subcylindrical................................................................................ 2
2(1) Male with an ‘antennae­like’ appendage between eyestalk and antennae; Americas,Galapagos Islands ..................................................................... Dendrocephalus
2' Male without an ‘antenna­like’ appendage .............................................................. 3
3(2) Basal portion of penes each with a large triangular carina, extending ventrally; Africa, Middle East, to India .............................................. Carinophallus gen. nov.
3’ Basal portion of penes without enlarged carinae ..................................................... 4
4(3) Penes with medial surface of rigid proximal portion with a dense, cornified patch of denticles, everted penes with two longitudinal rows of spines one ventral and one medial; halobiont species .................................................................... Phallocryptus
4’ Penes with medial surface of rigid proximal portion without a dense patch of denticles; not usually halophiles ...................................................................................... 5
5(4) Everted penes without a single, large, proximally directed, chitinized spine; E verted penes densely covered ventrally or laterally with spines or denticles, and lateral surface bearing one or more longitudinal rows of spines; Australia, Eurasia, Africa ................................................................................................... Branchinella
5' Everted penes with a single large, ventral, proximally directed, chitinized spine; male cephalic appendage with some branches spirally coiled; South America ......... ..................................................................................................................... Gurneya
description: Published as part of Rogers, D. Christopher, 2006, A genus level revision of the Thamnocephalidae (Crustacea: Branchiopoda: Anostraca), pp. 1-25 in Zootaxa 1260 on pages 19-20, DOI: 10.5281/zenodo.173180