Coronatella, Dybowski & Grochowski, 1894

DAMME, KAY VAN, SINEV, ARTEM YU & DUMONT, HENRI J., 2011, Separation of Anthalona gen. n. from Alona Baird, 1843 (Branchiopoda: Cladocera: Anomopoda): morphology and evolution of scraping stenothermic alonines, Zootaxa 2875 (1), pp. 1-64: 57-58

publication ID

http://doi.org/ 10.11646/zootaxa.2875.1.1

persistent identifier

http://treatment.plazi.org/id/0390471D-FFC3-1816-FF22-D01F6B34C82E

treatment provided by

Felipe

scientific name

Coronatella
status

 

Similarity with Coronatella  

Coronatella   and Anthalona   gen. n. are similar enough for earlier authors to regard A. verrucosa   as a member of Coronatella   rectangula- group (e.g., Daday 1910, Jenkin 1934; A. rectangula   -group). Also the presence of tubercles in both, has lead to confusion (e.g., Johnson 1956b). Important similarities include ( Van Damme & Dumont 2008b): 1) five pairs of limbs with reductions, typical for the Coronatella- branch (IDL with two setae, reduction of anterior setae in P1, exIII with six setae, no gnV); 2) specialized setal armature (IDL on P1); 3) The A. monacantha   group (to be removed from Alona   ) has all characters of Coronatella   , but some peculiarities of Anthalona   (strong armature IDL on P1, denticle on labrum) as well, hence seems intermediate; 4) In general dimensions of body and postabdomen, Coronatella   and Anthalona   gen. n. look nearly identical.

Coronatella   and Anthalona   seem both natural assemblages with a separate evolution. The head pore configuration is distinct and stable in each genus (two + cosmaria in Anthalona   versus three + no lateral pores in Coronatella   ). The phylogenetic importance of head pores in the Aloninae   may be overrated, but the difference is significant in that the typical head pore type arose only once in an ancestral Anthalona   , maybe even from the Karualona   type. It gave rise to a subtle diversity of head pore arrangements in Anthalona   . The same can be said for postabdomen armature (lateral spines thicker and basal spine shorter in Anthalona   ) and other specific characters ( Fig. 29). In the antennae of Coronatella   and Anthalona   , strong changes and specialisations have occurred independently, suggesting important plasticity in these traits (e.g., C. holdeni   and A. acuta   ). The limb characters shared by both Coronatella   and Anthalona   gen. n. are mainly reductions. As a general trend in the evolution of these microcrustaceans (reduction of setae), such reductions may either have arisen independently or stem from a common ancestor.

Similarity in morphological form may be a result of a reversal, close common ancestry, parallel evolution or convergence. Homoplasy may occur under similar adaptive pressures or by evolutionary constraints (constraints to structural solutions; e.g., Wake 1991). The similarities in body size and postabdomen between Coronatella   and Anthalona   may result from such constraints, although details on their feeding and ecology are yet to be investigated. Reductions on limbs in Coronatella   and Anthalona   may also be correlated with miniaturization; both are among the smaller Aloninae   genera. In the Alona   guttata- group for example, which belongs to an entirely different lineage (of six-limbed Alona   ), reductions seem correlated with a decrease in body size. In any case, Anthalona   and Coronatella   are examples of the typical general small, successful Alona   body shape. However, closer examination shows that comparative body shapes of Anthalona species   are not so similar ( Figs 27–28).

Coronatella   and Anthalona   gen. n. do not necessarily share a close common ancestor. Evolutionary pressures under similar conditions and/or constraints in the Aloninae   “Bauplan” may have lead to homoplasy in external and internal characters, with body shape, postabdomen, even limbs, similar. It results in a small model, successful in littoral environments. An independent test to see whether Coronatella   and Anthalona   share a close common ancestor is by molecular analysis (Van Damme & Dumont, unpubl.), not included in this study. It is this general small “ Alona   ” body shape that caused many of our historical taxonomical problems in the lump genus (Van Damme et al., 2010)

Kingdom

Animalia

Phylum

Arthropoda

Class

Branchiopoda

Order

Diplostraca

Loc

Coronatella

DAMME, KAY VAN, SINEV, ARTEM YU & DUMONT, HENRI J. 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

A. acuta

Van Damme, Sinev & Dumont 2011
2011
Loc

Anthalona

Van Damme, Sinev & Dumont 2011
2011
Loc

Karualona

Dumont & Silva-Briano 2000
2000
Loc

Aloninae

Dybowski & Grochowski, 1894 emend. Frey 1967
1967
Loc

A. verrucosa

Sars 1901
1901
Loc

A. monacantha

Sars 1901
1901
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Coronatella

Dybowski & Grochowski 1894
1894
Loc

Alona

Baird 1843
1843