Iguanodons by Gerhard Heilmann, 1928
Source: Gerhard Heilmann 1928, »A restoration of Iguanodon bernissartensis«, Palaeobiologica Dollo-Festschrift (Vienna & Leipzig: Emil Haim & Co.), pp. 101-102, 1 plate.
Heilmann, who became famous for his book The Origin of Birds, published a little-known, short piece about Iguanodon a few years later in an issue of Othenio Abel’s Palaeobiologica, dedicated to the Belgian palaeontologist Louis Dollo. In a lot of ways, this Iguanodon is much more ‘old-fashioned’ than his dynamic restorations in The Origin of Birds.
First, it stands much more vertically. Although its tail doesn’t rest on the ground in the way that, for example, Charles Knight reconstructed his bipedal dinosaurs, it is still an altogether more stodgy-looking affair. This is further enhanced by the fact that the animal now looks quite iguana- (and therefore reptile-) like. Interestingly, an accompanying line drawing the animal’s head decreases that effect, but it’s still not quite as ‘modern’-looking as the 1926 reconstruction. In case you were wondering, Heilmann himself explains that:
»this reconstruction [...] does not in the main features differ much from my former one (The Origin of Birds, Fig. 111), but the two running animals did not resemble reptiles at all«.
In general, I think Heilmann’s pen drawings are much more effective than his colour work (the famous Archaeopteryx reconstruction being an exception, perhaps). It is interesting to see him reverting to a more conservative approach here, although I’m unsure where the significance of that may lie.
However, as I’ve written before, it is clear that from the first drawings in 1912, Heilmann’s reconstructions become progressively more and more restrained. That is particularly the case with regard to the stance he lets his animals adopt: from the fighting Archaeopteryxes of 1914 we end with the courting couple we know so well from the 1926 edition.
Heilmann’s entire essay is here. Go here for more examples of his artwork.

