http://www.collembola.org/publicat/integum/corneula.htm Last updated on 2006.12.23 by Frans Janssens
Checklist of the Collembola: Some notes on the Ultrastructure of the Cuticula. Corneula

Luc De Bruyn, Department of Biology, University of Antwerp (RUCA), Antwerp, B-2020, Belgium
Jean-Auguste Barra, Laboratoire de Zoologie, Université Louis Pasteur, Strasbourg, 67000, France
Frans Janssens, Department of Biology, University of Antwerp, Antwerp, B-2020, Belgium

This page is under construction.

Differentiation of the corneular epicuticula

Barra, 1971:322-353 describes four different types of corneular ultrastructure:

Corneula with microtubercular ultrastructure

Fig.1. Corneula with microtubercular ultrastructure of
Tomocerus problematicus
Barra, 1971.
The corneula has a surface ultrastructure identical to the epicutilar ultrastructure of the surrounding integument (Fig.1 after Barra, 1971:Fig.1.A; x 6000). The size of the microtubercular tesselation on the corneula is smaller than that of the integument. This type of corneula is found with Lepidocyrtus curvicollis, Pseudosinella duodecimoculata, Tomocerus minor and Tomocerus problematicus (Barra, 1971:327).

Corneula with smooth surface

Fig.2. Corneula with smooth surface of
Hypogastrura purpurescens
Barra, 1971.
The corneula has a smooth surface and lacks a microtubercular ultrastructure (Fig.2 after Barra, 1971:Fig.1.B; x 6000). This type of corneula is found with species of the genus Hypogastrura, more in particular with Hypogastrura tullbergi and Hypogastrura purpurescens (Barra, 1971:327).
In Pseudachorutini, an intermediate arrangement is found: the microtubercular tesselation is present only at a basal ocellar border (Barra, 1971:Fig.2.A). This intermediate arrangement is also found with Neanura muscorum (Barra, 1971:329).
In Isotoma aff. saltans, the hexagonal tesselation is also completely lacking on the surface of the ocelli (Eisenbeis & Wichard, 1985:227(Tafel 103 fig.e)).

Corneula with parallel ridges

Fig.3a. Epicuticular ultrastructure of ocellus of
Pogonognathellus flavescens
Eisenbeis & Wichard, 1985.
Fig.3b. Differentiation in the epicuticular ultrastructure of the corneula of the ocellus of Pogonognathellus flavescens
Eisenbeis & Wichard, 1985.

In Pogonognathellus flavescens, a differentiation of the surface structure of the ocelli is observed (Fig.o,p): at the base of the ocellus the typical microtubercular pattern is found but it does not occur at the centre of the corneula (Eisenbeis & Wichard, 1985:205(Tafel 92 fig.b & fig.c)). Note also the size gradient of the hexagons on the ocellus compared to those on the integument of the head.

Fig.3c. Corneula with parallel ridges of
Pogonognathellus longicornis
Barra, 1971.

Fresnell effects? To be completed.

Corneula with nipples

Fig.4. Corneula with nipples of
Dicyrtoma atra
Barra, 1971.

To be completed.