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Nordus

Stylianos Chatzimanolis
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taxon links [up-->]Nordus fungicola [down<--]Xanthopygina Interpreting the tree
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phylogeny after Chatzimanolis 2005
Containing group: Xanthopygina

Introduction

The genus Nordus Blackwelder, 1952, contains 38 species and was recently revised by Chatzimanolis (2004). Nordus is distributed from southern Mexico to northern Argentina, with the highest diversity of species in South America and especially in Ecuador, Peru and Bolivia. These beetles range in size from 7 to 13 mm, and most species are brightly colored. The genus was originally proposed by Nordmann in 1837 as the genus Brachydirus.

Characteristics

There are several different color patterns in Nordus; most species have (probably aposematic) golden-orange coloration on the head, pronotum and elytra. Other species have the pronotum and elytra golden-orange, and the head anteriorly black and posteriorly orange, or head, pronotum and elytra are black; while one species, N. speciosus, has the head, pronotum and elytra metallic green. Among all genera in Xanthopygina, Nordus exhibits probably the most dramatic structural modifications in secondary sexual characters (on abdominal sterna VII, VIII and IX) and in the colouration of different species. The color of the abdomen is always black (except in N. portokalis, where it is orange) with a bright yellow apex (part of segment VII and segment VIII).

Nordus can be distinguished from other xanthopygines by the combination of the following structures:

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From left to right, head of N. simplex showing the punctuation pattern; VIII abdominal stergum of N. terminalis and N. styloceros respectively, showing the secondary sexual structures on this segment. Images © 2003 Stylianos Chatzimanoli.

Discussion of Phylogenetic Relationships

The tree shown above is the strict consensus of four trees. The sister-group relationships of most species are supported by multiple synapomorphies and high Bremer support values. Nordus major is sister to all remaining Nordus species. The overall shape of the head, which exhibits great allometric variation in proportion to the size of the pronotum, resembles the overall shape of the head in species of the genus Xanthopygus. This species, of course, clearly is a member of Nordus because it has all the above mentioned synapomorphies, but probably it has retained the plesiomorphic general shape of the head.

The phylogeny shows that the probably aposematic golden-orange coloration evolved in the ancestor of Nordus, although it is not clear whether this happened in the immediate ancestor of Nordus, or is shared with other genera because the phylogenetic relationships among xanthopygines are unknown.

References

Chatzimanolis S. 2004. A revision of the neotropical genus Nordus (Coleoptera: Staphylinidae). Ent. Ab. 62(1):3-64.

Chatzimanolis S. 2005. Phylogeny of the neotropical rove beetle genus Nordus (Coleoptera: Staphylinidae) with a special reference to the evolution of coloration and secondary sexual characters. Sys. Ent. 30:267-280.

Title Illustrations
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Scientific Name Nordus velitaris
Specimen Condition Dead Specimen
Identified By Stylianos Chatzimanolis
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © Stylianos Chatzimanolis
Scientific Name Nordus fungicola
Location Barro Colorado Island, Panama
Specimen Condition Live Specimen
Identified By Stylianos Chatzimanolis
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © Stylianos Chatzimanolis
Scientific Name Nordus speciosus
Specimen Condition Dead Specimen
Identified By Stylianos Chatzimanolis
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © Stylianos Chatzimanolis
About This Page

Stylianos Chatzimanolis
University of Tennessee at Chattanooga

Correspondence regarding this page should be directed to Stylianos Chatzimanolis at

Page: Tree of Life Nordus. Authored by Stylianos Chatzimanolis. The TEXT of this page is licensed under the Creative Commons Attribution License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Chatzimanolis, Stylianos. 2005. Nordus. Version 18 December 2005. http://tolweb.org/Nordus/10274/2005.12.18 in The Tree of Life Web Project, http://tolweb.org/

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