On the Canary Islands Lanzarote and Fuerteventura I several times found large
numbers of some fossil or subfossil insect nest, that might well have been made
by one or more Anthophora species. The nests are about oval, 2-3 cm long and
1.5-2 cm wide; almost always they are single. No interior lining is
recognizable, but the interior is very smooth. The cells are made of sandy loam
or (more rarely) pure loam, that has been hardened by the fossilization process
to a variable degree. The wall thickness is approx. 3 mm. The opening, at one
of the poles, mostly has a narrow rim, has been closed but is, probably
subsequently, perforated by a hole of about 7 mm. In perhaps 50% of the nests
there is one, sometimes more, opening in the side as well.
 
That they are fossil is certain. I found in Fuerteventura a intertidal rock
formation of a few square meters that was entirely composed of these nests. In
Lanzarote I once found a small erosion gulllly that had nicely made a steep cut
of several meters in the soil, disclosing that the soil contained thousands of
these nests, down to the very bottom of the cut. But usually they are found,
together with huge numbers of shells of landsnails strewn over the surface of
flats of moving sand, where they evidently have been blown bare by the wind.
 
As far as I know, the nests are not found, at least not in these numbers, on
the other, i.e. western islands of the Canarias. Except for Gran Canararia,
these islands have no dunes, which might be part of the explanation.
 
In the entomological literature pertaining to the Canary Islands (there is a
good checklist by A. Machado) I could not find a reference to the these nests.
In the geological literature (Rothe) they are mentioned indeed, and called
RAntophoraS. This spelling error is signficant, because it is typically a
Spanish error, and suggests to me that all identifications go back to one
single man, a Spanish geologist called Bravo. The book in which he refers to
the nests seems not to be available in The Netherlands, however. Secondary
sources tell that Bravo had seen an Anthophora making this type of nest in the
Orotava region (Tenerife) - which is a very different habitat indeed.
 
I should add, finally, that closely similar nests are sometimes offered for
sale in fossils shop, with "Australia" as origin, but I cannot testify that
this is genuine.
 
Does this long (apologies) description rings a bell to some of you on the list?
The apidological literature has brought me nowhere, so far. Thanks in advance
for any help!
 
Willem Ellis
(Inst. of Taxonomic Zoology, dept. Entomology, Univ. of Amsterdam).