Fritz Müller and the first phylogenetic tree

I have previously noted that the first empirical phylogenetic tree apparently was published by St George Jackson Mivart in late 1865, a full 6 years after Charles Darwin released On the Origin of Species (Who published the first phylogenetic tree?). Mivart was not necessarily the first to start producing such a tree, but he got into print first. For example, Franz Martin Hilgendorf wrote a PhD thesis in 1863 for which he produced a hand-drawn tree, but he did not actually include the tree itself in the thesis (The dilemma of evolutionary networks and Darwinian trees). Also, Ernst Heinrich Philipp August Haeckel claimed to have started work on his series of phylogenetic trees in 1864, but the resulting book, Generelle Morphologie der Organismen, was not published until 1866 (Who published the first phylogenetic tree?).

Another actor in this series of events was Fritz Müller, who can also be considered to have published a tree first, in 1864, albeit a very small one.

Johann Friedrich Theodor Müller (1822–1897)

Müller was born in Germany, but in the 1850s he emigrated to southern Brazil with his brother and their wives. As a naturalist in the Atlantic forest, he studied the insects, crustaceans and plants, and he is chiefly remembered today as the describer of what we now call Müllerian mimicry (the phenotypic resemblance between two or more unpalatable species).

Heinrich Bronn's German translation of the Origin appeared in 1860, and Müller read it and agreed with its central thesis (as did Hilgendorf and Haeckel). Indeed, in 1864 he published a book discussing some of the empirical evidence that he adduced with regard to the Crustacea:

Für Darwin
Verlag von Wilhelm Engelman, Leipzig.

The book has 91 pages and 67 figures, and the Foreword is dated 7th September 1863. Several copies are available in Google Books (here, here, here).

In this book Müller described the development of Crustacea, illustrating that crustaceans and their larvae could be affected by adaptations and natural selection at any growth stage. He discussed in detail how living forms diverged from ancestral ones, based on his study of aerial respiration, larvae morphology, sexual dimorphism, and polymorphism.

Darwin read the book, and began a life-long correspondence with Müller (ultimately some 60 letters having been exchanged between them). Subsequently, Darwin commissioned an English translation of the book, and in 1869 published it with John Murray on commission (ie. taking the risk himself). Darwin printed 1000 copies but it apparently was not a great success:

Facts and Arguments for Darwin
Translated from the German by W.S. Dallas
John Murray, London.

The book has 144 pages and 67 figures, and the Translator's Preface is dated 15th February 1869. A copy is available in the Biodiversity Heritage Library (here).

The following quotes are from this English translation [Note that Müller's unnecessarily convoluted sentences exist in the original German — this writing style is one reason why the book is not as well known as the works of Darwin and Wallace]:

It is not the purpose of the following pages to discuss once more the arguments deduced for and against Darwin's theory of the origin of species, or to weigh them one against the other. Their object is simply to indicate a few facts favourable to this theory ...

When I had read Charles Darwin's book 'On the Origin of Species,' it seemed to me that there was one mode, and that perhaps the most certain, of testing the correctness of the views developed in it, namely, to attempt to apply them as specially as possible to some particular group of animals ...

When I thus began to study our Crustacea more closely from this new stand-point of the Darwinian theory,—when I attempted to bring their arrangements into the form of a genealogical tree, and to form some idea of the probable structure of their ancestors,—I speedily saw (as indeed I expected) that it would require years of preliminary work before the essential problem could be seriously handled ...

But although the satisfactory completion of the "Genealogical tree of the Crustacea" appeared to be an undertaking for which the strength and life of an individual would hardly suffice, even under more favourable circumstances than could be presented by a distant island, far removed from the great market of scientific life, far from libraries and museums—nevertheless its practicability became daily less doubtful in my eyes, and fresh observations daily made me more favourably inclined towards the Darwinian theory.

In determining to state the arguments which I derived from the consideration of our Crustacea in favour of Darwin's views, and which (together with more general considerations and observations in other departments), essentially aided in making the correctness of those views seem more and more palpable to me, I am chiefly influenced by an expression of Darwin's: "Whoever," says he ('Origin of Species' p. 482), "is led to believe that species are mutable, will do a good service by conscientiously expressing his conviction."

So, for the reason stated, Müller did not produce a complete phylogeny in the book. However, of particular interest to us is the figure on page 6 of the original German edition (page 9 of the translation). It turns out to be a pair of three-taxon statements concerning species of Melita (amphipods), as shown in the figure above (original) and below (translation). Müller has this to say:

[There are five] species of Melita ... in which the second pair of feet bears upon one side a small hand of the usual structure, and on the other an enormous clasp-forceps. This want of symmetry is something so unusual among the Amphipoda, and the structure of the clasp-forceps differs so much from what is seen elsewhere in the this order, and agrees so closely in the five species, that one must unhesitatingly regard them as having sprung from common ancestors belonging to them alone among known species.

This is as clear a statement of synapomorphy, and its relationship to constructing a phylogeny, as you could get; and so we could credit Müller with having produced an empirical phylogenetic tree (the one on the left in the figures).

Equally interestingly, Müller then goes on to consider a potentially contradictory character: the secondary flagellum of the anterior antennae, which is missing in one species. This would produce a different three-taxon statement (shown on the right in the figures). He resolves the issue by suggesting that the flagellum might be similar to the situation in other species, where it is "reduced to a scarcely perceptible rudiment—nay, that it is sometimes present in youth and disappears at maturity". This is a clear example of the character conflict that arises when trying to construct an empirical phylogeny; and it was also encountered by Mivart in his studies of primate skeletons (Is this the first network from conflicting datasets?).

Conclusion

Müller did not publish a complete phylogeny, but instead discussed how to produce one, and illustrated the practicality (and necessity) of doing so. In the process, he produced a simple three-taxon statement (which is not even numbered as a figure). Nevertheless, this cladogram is technically the first in print, pre-dating Mivart by a year. Darwin was right to recognize its importance, although he seemed to take a while to bring it to the attention of the English-speaking public. Furthermore, Müller was apparently the first to encounter the empirical difficulty of how to deal with conflicting data, which would produce different phylogenetic trees. This is an issue that is just as important today as it was then.

What is "Haeckel's Tree of Life"?

The "Tree of LIfe" is an expression that you will find all over the web, usually referring to little more than a phylogenetic tree with only a few species in it, and certainly not all of Life, nor even the major groups of LIfe. More specifically, however, it seems commonly to refer to any tree that has Homo sapiens in it.

One tree that has intrigued me is found on Wikipedia's page called Tree of life (biology). It is labelled as "Haeckel's Stambaum der Primaten (1860s)", but in the text it is referred to as "the first sketch of the famous Haeckel's Tree of Life in the 1870s which shows 'Pithecanthropus alalus' as the ancestor of Homo sapiens."

The original JPEG file of the tree, dated 18 February 2009, has a compromise between these two contradictory statements: "The first sketch of the famous Heackel's Tree of Life which shows 'Pithecanthropus alalus' as the ancestor of Homo sapiens. Date: 1860s." No source is given for the picture.

Ernst Haeckel was the most famous popularizer of phylogenetic trees in the 19th century (he called them Stammbaum, literally "stem tree"). However, the illustration itself is not in the style of Haeckel's trees from the 1860s, which were drawn as realistic trees (see Who published the first phylogenetic tree?), nor is it in the style of his most famous tree from the 1870s, which is drawn as an oak tree (see Evolutionary trees: old wine in new bottles?). So, I decided to trace the history of this tree.

Haeckel published a slightly modified version of the sketch, with a different title, in:

Ernst Haeckel (1899)
Ueber Unsere Gegenwärtige Kenntniss vom Ursprung des Menschen.
[About Our Current Knowledge of Human Origins]
Emil Straws, Bonn.

It is worth noting that all of the names along the central axis are hypothetical, except for Homo sapiens. Pithecanthropus alalus, however, came to be associated with what is colloquially called Java Man, now named Homo erectus.

As far as I can determine, the hand-drawn version of the illustration (ie. the one in Wkipedia) first appeared in:

Herbert Wendt (1954)
Ich Suchte Adam: Roman einer Wissenschaft.
[In Search of Adam: a Science Novel]
Zweite, erweiterte Auflage. [Second, enlarged edition]
Grote Verlag, Hamm.

It did not appear in the first edition of the book, published the year before. It appears as Figure 22 (page 310):

Abb. 22:
Haeckels klassisch gewordener Menschenstammbaum, eigenhändig als erste Skizze entworfen – ein historisches Dokument. [Haeckel's classic people pedigree, designed by hand as the first sketch – a historical document.]

Note that, contrary to the claim, this is not the first pedigree from Haeckel, nor is it even the first primate pedigree from him. The source of the document is noted on page 581 as:

Verzeichnis der Textabbildungen
Abb. 22: Haeckels Stammbaum des Menschen. (Prof. Dr. Heberer, Göttingen)

Gerhard Heberer was a German anthropologist and phylogeneticist, who studied Haeckel's work closely. He apparently passed a copy of the illustration to Herbert Wendt when the latter was expanding his book with many more illustrations. This book was a best-seller from the start, going through five German editions, before re-appearing in 1961 as Ich Suchte Adam: Die Entdeckung des Menschen [The Discovery of Humans], whence it went through another seven editions. It was translated into English, appearing in 1955 as I Looked for Adam, in 1956 as In Search of Adam: The Story of Man's Quest for the Truth About His Earliest Ancestors, and in 1972 as From Ape to Adam: Search for the Evolution of Man. It was also translated into several other languages (including Swedish in 1955 as I Urmänniskornas Spår: Förhistoriens Forskaräventyr).

The hand-drawn tree has appeared in print at least twice since its first appearance in Wendt's book. The most important of these is in:

Thomas Junker and Uwe Hoßfeld (2001)
Die Entdeckung der Evolution: Eine revolutionäre Theorie und ihre Geschichte.
[The Discovery of Evolution: a Revolutionary Theory and its History]
Wissenschaftliche Buchgesellschaft, Darmstadt.

The picture appears as Figure 18 on page 125:

Abb. 18: Handschriftlicher Entwurf des Stammbaums der Primaten von Ernst Haeckel (1895). (Bildmaterial im Nachlass Heberer; im Besitz von Uwe Hoßfeld).
[Hand-drawn sketch of the family tree of primates by Ernst Haeckel (1895). (Artwork in the estate of Heberer; in the possession of Uwe Hoßfeld.]

Uwe Hoßfeld has told me: "I got the whole archive material from the Heberer family in 1990 and found the photo in his diaries." This explains the later history of the sketch, although not how Gerhard Heberer acquired the photo in the first place.

The date 1895 makes much more sense than do the 1860s and 1870s dates (as given in Wikipedia), especially given the publication date of the printed version.

The other appearance of the hand-drawn tree is in this book:

Winfried Henke and Ian Tattersall (editors) (2007)
Handbook of Paleoanthropology, Volume 1.
Springer‐Verlag, Berlin.

The tree appears as Figure 1.4 on page 16 (in the chapter by Winfried Henke 'Historical overview of paleoanthropological research'), and is labelled: "First pedigree designed by Ernst Haeckel". As noted above, it is not the first pedigree from Haeckel, nor the first primate pedigree from him. Winfried Henke has told me that he got the sketch from Wendt's book.

As a final point, Haeckel's hand-drawn trees usually seem to match the published versions rather more closely than the one above does. For example, here is the hand-drawn original of his famous oak tree. Perhaps, the more stick-like tree was not treated as being a "real" picture.

Thanks to Winfried Henke and Uwe Hoßfeld for their email correspondence regarding my quest.

A modern Haeckel-like network

In a previous blog post I noted that Ernst Haeckel's first phylogenetic trees (published in Generelle Morphologie der Organismen, 1866) were distinctive in that many, if not most, of the labels occur in the spaces between the terminal twigs, like seeds enclosed within a fruit. In contrast, most other phylogenetic trees, both then and now, distinctly label the individual leaves/twigs.

I have, however, come across the Haeckel-like design in at least one recent place: the Darwin's Library blog for 19 April 2010. Note that the figure, reproduced here, is actually a network, as the branches fuse in at least two places, indicating hybridization of ideas.

Mathematically, I guess that we could best interpret the labels as referring to the nodes rather than to  either of the two terminal twigs.

This phylogeny contains one other intriguing feature — the branch leading to both "email" and "blog" diverges from the branch leading to "scroll" and "codex", whereas I would have thought that blogs would be related to "newspaper" and "magazine", for example, which are descendants of "codex". Emails are related to letters, which do not appear in the phylogeny, but could, I guess, be on the long branch leading to "email".

Who published the first phylogenetic tree?

It is usually acknowledged that Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (1744-1829), published an early evolutionary tree (Lamarck 1809). However, his published trees differ from our modern phylogenetic diagrams in having contemporary higher-level taxonomic groups at both the internal and external nodes, so that each tree represents a transformation series among the taxonomic groups. Thus, while his trees were based on the idea of transmutation, they do not match our current type of tree.

The later published trees of, for example, Charles-Hélion de Barbançois, Hugh Edwin Strickland, and Alfred Russel Wallace, followed the style of Lamarck. Other trees published in the first half of the 19th century, such as those of Jean Louis Rodolphe Agassiz, Augustin Augier, Heinrich Georg Bronn, and Edward Hitchcock, were not intended to be evolutionary diagrams, because their authors did not believe in evolution (Ragan 2009; Tassy 2011).

Charles Darwin (1859) is usually credited as being the originator of modern phylogenetic trees, with contemporary taxa at the leaves and ancestors at the internal nodes. Therefore, an answer to the question posed in the title must involve a post-Darwinian person. There appear to be four candidates for who published the first empirical Darwinian tree, in the period 1865-1866, two of them palaeontologists and two comparative morphologists, two with strong religious beliefs and two apparently without, and including one Englishman, one Frenchman and two Germans. I list them here in the probable order of publication.

Note: For another early tree, see the blog post Fritz Müller and the first phylogenetic tree.

St George Jackson Mivart (1827-1900)

St George Mivart was a comparative morphologist who was an early British convert to Darwinism, although he later fell out with Thomas Henry Huxley and therefore with Darwin. His work was principally on the comparative anatomy of primates, for which he provided very detailed comparisons of the skeletons of a large number of species, notably in Mivart (1865) and Mivart (1867).

The paper by Mivart (1865) therefore seems to be the first publication to contain an explicitly Darwinian tree. This is ironic, given the fact that Mivart later became one of Darwin's strongest critics. That it took 6 years (from 1859) for a biologist to produce such a tree may reflect the fact that Darwin himself published only a single theoretical sketch, thus leaving others to work out how to apply his ideas to empirical data.

The 1865 paper was read before the Zoological Society of London on 27 June 1865, and then appeared as a regular part of the Society's journal later that year (see Dickinson 2005). It was based on a detailed osteological analysis of the spinal columns of 29 primate genera. As noted by Bigoni & Barsanti (2011): "Not only does he use taxonomic names still largely in use today, but, surprisingly, Homo is not the apex or culmination of evolution ..., in fact it is placed on a lateral diverging branch. This position of humans provides his tree with a particularly modern appearance and is perfectly consistent with the trees or bushes that Darwin drew." Mivart's paper is available from the publishers John Wiley & Sons and also the Biodiversity Heritage Library.

Unfortunately, Mivart's tree does deviate from Darwin's ideas in that the leaves and many of the branches refer to higher taxonomic groups, rather than to species. In this sense his trees look similar to Ernst Haeckel's (see below), although it is doubtful that they were constructed in the same way. Note that Mivart's labels occur along the terminal twigs, rather than at their end, as his contemporaries chose to present them (and as we do today).

Also, being based on different data sets, the 1867 tree (based on the appendicular skeleton, or limbs) does differ in topology from the 1865 one (based on the axial skeleton, or spinal column), thus foreshadowing a problem with phylogeny reconstruction from different data sources that continues to this day (see this later blog post). Mivart explicitly noted in a letter to Darwin (1870): "The diagram in the Pro. Z. Soc. expresses what I believe to be the degree of resemblance as regards the spinal column only. The diagram in the Phil. Trans. expresses what I believe to be the degree of resemblance as regards the appendicular skeleton only" (Darwin Correspondence Project letter 7170). Indeed, in the 1865 paper Mivart also noted that the data for the spinal column "lead to an arrangement of groups and an interpretation of affinities somewhat differing from, yet in part agreeing with, the classification founded on cranial and dental characters".

Mivart's work is discussed in detail by Bigoni & Barsanti (2011). Mivart's views on evolution and theology are presented in Mivart (1871).

From Mivart (1865) p. 592. Click to enlarge.

From Mivart (1867) p. 425. Click to enlarge.

Franz Martin Hilgendorf (1839-1904)

Franz Hilgendorf was a palaeontologist, among other zoological pursuits, although he is relatively unknown today. He was one of the first Germans to accept Darwin's ideas (Reif 1986), and he is also credited with being the first to introduce evolutionary theory into Japan (c. 1873) (Yajima 2007). He could also have been the first to publish a Darwinian tree, but he did not actually do it.

Hilgendorf's PhD work was on the fossil gastropods of the middle Miocene basin at Steinheim, in southern Germany, which he visited in 1862. He studied the morphological variation, in the different stratigraphic layers, of the various fossil forms of what he referred to as Planorbis multiformis. The resulting thesis (Hilgendorf 1863) was passed in April 1863 but was otherwise unpublished, and it apparently contained no images. Nevertheless, Hilgendorf discussed in detail the relationship between a complete stratigraphic series of fossils and Darwin's evolutionary ideas, concluding that the Planorbis fossils could be arranged in a phyletic tree; and Reif (1983) found that Hilgendorf's notes did, indeed, contain a preliminary phylogenetic diagram. Reif (1983) presents a version of this phylogeny based on Hilgendorf's notes, which is also reproduced by Janz (1999).

Hilgendorf may thus have been the first to produce a Darwinian tree, even though he did not publish it. His ideas were Darwinian by including ancestral and descendant forms, splitting of lineages, and gradual transition between forms, with the ancestral taxa being varieties, not higher taxa. Interestingly, in the thesis Hilgendorf also raised the possibility that two of the lineages may have fused. He noted: "This does not fit the nice picture of a tree with many branches that Darwin presented to illustrate the descent of species — the branches of a tree never fuse again" [translation taken from Janz 1999].

Hilgendorf then made another excursion to the Steinheim basin in 1865, and wrote up the results for publication, this time with an explicit tree showing the relationship between the 19 different fossil forms that he recognized. This was read as a paper before the Royal Prussian Academy of Sciences on 19 July 1866, and was apparently published simultaneously as an offprint (Hilgendorf 1866). The paper then appeared as a regular part of the Academy's journal (Hilgendorf 1867) — these two versions are evidently identical save only the absence of the subtitle in the latter [which translates as "an example of morphological change through time"]. This is thus Hilgendorf's first published Darwinian tree.

There are actually two versions of the tree in the paper, as shown here, taken from the Biodiversity Heritage Library. The first tree emphasizes which stratigraphic layers each morphological form occupies (there are ten layers), whereas the second tree emphasizes the forms themselves. There is no suggestion of lineage fusion in either tree.

Hilgendorf's work is discussed in detail by Reif (1983), and more generally by Janz (1999).

From Hilgendorf (1867) p. 479. Click to enlarge.

From Hilgendorf (1867) after p. 502. Click to enlarge.

Jean Albert Gaudry (1827-1908)

Albert Gaudry was a palaeontologist who was one of the very few French scientists to promote Darwinian evolution. Indeed, Darwin noted in a letter to Jean Louis Armand de Quatrefages de Bréau (1870): "It is curious how nationality influences opinion: a week hardly passes without my hearing of some naturalist in Germany who supports my views, & often puts an exaggerated value on my works; whilst in France I have not heard of a single zoologist except M[onsieur] Gaudry (and he only partially) who supports my views" (APS 379; An Annotated Calendar of the Letters of Charles Darwin in the Library of the American Philosophical Society 1799-1882, p. 212).

The paper by Gaudry (1866) was a separately paginated offprint of the second chapter of part 1 (pp. 325-370) of a larger work about the fossil mammals from the late Miocene locality of Pikermi in Attica, in Greece, which was completed in 1867 (Animaux Fossiles et Géologie de l’Attique d’après les recherches faites en 1855–56 et en 1860 sous les auspices de l’Académie des sciences). In this offprint Gaudry expressed his views on palaeontology and evolution. He noted that the Pikermi fossils showed characteristics of two or more groups of animals, so that he could see the passage from order to order, family to family, genus to genus, and species to species in these intermediate forms.

He included five trees showing the relationships among different groups of extant and extinct fossil mammals, within a stratigraphic framework. The pictures shown here are taken from Google Books. I do not know exactly when this offprint was published, but Darwin acknowledged on 17 September 1866 that he received it "some time ago", so that it might pre-date Hilgendorf's own offprint.

As emphasized by Tassy (2006, 2011), Gaudry's trees were Darwinian by including ancestral and descendant species, splitting, gradualism and extinction, with the ancestral taxa being species or sub-species, not higher taxa. However, Gaudry did not fully embrace Darwinism, for religious reasons. As Darwin noted in a letter to Gaudry thanking him for a copy of the 1866 offprint: "I will venture to make one little criticism, namely that you do not fully understand what I mean by 'the struggle for existence', or concurrence vitale; but this is of little importance as you do not at all accept my views on the means by which species have been modified." (Darwin Correspondence Project letter 5213). Gaudry attributed evolutionary change to God, rather than to natural selection, as indicated in the closing sentence of his 1866 work: "Mais, nous n'eu douterons pas, l'artiste qui pétrissait était le Créateur lui-même, car chaque transformation a porté un reflet de sa beauté infinite."

Gaudry's work is discussed in detail by Tassy (2006), if you read French, and more briefly by Tassy (2011), if you do not.

From Gaudry (1866) p. 36. Click to enlarge.

From Gaudry (1866) p. 38. Click to enlarge.

From Gaudry (1866) p. 41. Click to enlarge.

From Gaudry (1866) p. 44. Click to enlarge.

From Gaudry (1866) p. 46. Click to enlarge.

Ernst Heinrich Philipp August Haeckel (1834-1919)

Ernst Haeckel is best known today as a comparative morphologist, but he was also an important popularizer of science, as well as a brilliant artist. He was an early German convert to Darwinism, and it has been noted that "more people by the turn of the century had learned of evolutionary theory through Haeckel's depictions than even from Darwin's own writings" (Richards 2011).

Haeckel actually coined the word "phylogeny" (along with many others, including "ontogeny" and "ecology"), and his first phylogenetic trees were published in the second volume of his two-volume opus about animal morphology (Haeckel 1866). Haeckel had the ambitious plan to reform the study of morphology, by synthesizing Darwin's ideas on genealogical descent with the transformational evolutionism of Lamarck, along with the German tradition of naturphilosophie (represented by Johann Wolfgang von Goethe). As noted by Hopwood (2006), for Haeckel: "evolution was the organizing principle of a cosmic synthesis that would unify science, religion, and art on a biological foundation."

There were eight trees in the book, showing the relationships between animals, plants and (for the first time) protists, and within plants and different animal groups. Haeckel used morphology to reconstruct the phylogenetic history of animals, and in the absence of fossils used embryology as evidence of ancestors. The pictures here are taken from the Biodiversity Heritage Library. These are frequently credited as being the first phylogenetic trees published, although Mivart, at least, published earlier. Haeckel claimed to have started the book "several years" before 1864, which is when he apparently started work on the phylogenetic trees (as he mentions in a letter to Darwin), but the Foreword is dated 14 September 1866.

Unfortunately, Haeckel's tree-construction method seems to have owed more to Lamarck than to Darwin (see Dayrat 2003), with the branches indicating morphological transformation among the named groups rather than strictly representing genealogy. Moreover, the trees show higher taxonomic groups at the internal branches, while Darwin treated them as representing extinct species. Thus, it is not clear just how Darwinian Haeckel really was. Indeed, Di Gregorio (2005) has noted: "Haeckel's view of evolution (or rather evolutionism) ..., from the very beginning, reminds one more of Jean-Baptiste Lamarck than Darwin."

One intriguing detail about Haeckel's early trees is that many, if not most, of the labels occur in the spaces between the terminal twigs, like seeds enclosed within a fruit. All of the trees shown above distinctly label the leaves, even though it it likely that their presentation format was derived independently of each other. Haeckel, on the other hand, appears to be much more vague about exactly what is being labelled. Perhaps this is a by-product of the fact that his images are distinctly tree-like in form, rather than being stick figures; or perhaps it comes from the rather speculative nature of many of the relationships proposed (the trees of Mivart, Hilgendorf and Gaudry were based on detailed empirical data, whereas Haeckel's were much more ambitiously hypothetical).

It is perhaps also worth noting that Haeckel first publicly endorsed Darwin's theory in his work on the Radiolaria (Haeckel 1862). On page 234 of that work (see the Biodiversity Heritage Library) he produced what he called a "Verwandtschaftstabelle der Familien, Subfamilien und Gattungen der Radiolarien", which is thus his first attempt at a genealogical diagram. It was not drawn as a tree, and is thus somewhat hard to interpret, but in the same chapter he discussed ancestral and transitional forms, and on pages 231–232 he made clear that he was attempting to implement Darwin's ideas.

Heackel's life and work are discussed in detail by Di Gregorio (2005) and Richards (2008).

From Haeckel (1866) Taf. I. Click to enlarge.

From Haeckel (1866) Taf. II. Click to enlarge.

From Haeckel (1866) Taf. III. Click to enlarge.

From Haeckel (1866) Taf. IV. Click to enlarge.

From Haeckel (1866) Taf. V. Click to enlarge.

From Haeckel (1866) Taf. VI. Click to enlarge.

From Haeckel (1866) Taf. VII. Click to enlarge.

From Haeckel (1866) Taf. VIII. Click to enlarge.

References

Bigoni, F., Barsanti, G. (2011) Evolutionary trees and the rise of modern primatology: the forgotten contribution of St. George Mivart. Journal of Anthropological Sciences 89: 93-107.

Darwin, C. (1859) On the Origin of Species by Means of Natural Selection, or the preservation of favoured races in the struggle for life. John Murray, London.

Dayrat, B. (2003) The roots of phylogeny: how did Haeckel build his trees? Systematic Biology 52: 515-527.

Dickinson, E.C. (2005) The Proceedings of the Zoological Society of London, 1859–1900: an exploration of breaks between calendar years of publication. Journal of Zoology, London 266: 427-430.

Di Gregorio, M.A. (2005) From Here to Eternity: Ernst Haeckel and scientific faith. Vandenhoeck & Ruprecht, Göttingen

Gaudry, A. (1866) Considérations Générales sur les Animaux Fossiles de Pikermi. F. Savy, Paris. 68 pp.

Haeckel, E. (1862) Die Radiolarien (Rhizopoda Radaria): Eine monographie. Verlag von Georg Reimer, Berlin.

Haeckel, E. (1866) Generelle Morphologie der Organismen: Allgemeine grundzüge der organischen formen-wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte descendenztheorie. — Band 1: Allgemeine anatomie der organismen. — Band 2: Allgemeine entwickelungsgeschichte der organismen. Verlag von Georg Reimer, Berlin.

Hilgendorf, F. (1863) Beiträge zur Kenntniß des Süßwasserkalkes von Steinheim. Unpublished PhD Dissertation. Philosophische Fakultät, Universität Tübingen, 42 pp.

Hilgendorf, F. (1866) Planorbis multiformis im Steinheimer Süßwasserkalk: ein beispiel von gestaltveränderung im laufe der zeit. Buchhandlung von W. Weber, Berlin, 36 pp.

Hilgendorf, F. (1867) Über Planorbis multiformis im Steinheimer Süsswasserkalk. Monatsberichte der Königliche Preussischen Akademie der Wissenschaften zu Berlin 1866: 474-504.

Hopwood, N. (2006) Pictures of evolution and charges of fraud: Ernst Haeckel’s embryological illustrations. Isis 97: 260–301.

Janz, H. (1999) Hilgendorf’s planorbid tree — the first introduction of Darwin’s theory of transmutation into palaeontology. Paleontological Research 3/4: 287–293.

Lamarck, J.-B. (1809) Philosophie Zoologique. Dentu et l'Auteur, Paris.

Mivart, StG. (1865) Contributions towards a more complete knowledge of the axial skeleton in the primates. Proceedings of the Zoological Society of London 33: 545-592.

Mivart, StG. (1867) On the appendicular skeleton of the primates. Philosophical Transactions of the Royal Society of London 157: 299-429.

Mivart, StG. (1871) On the Genesis of Species. Macmillan, London.

Ragan, M.A. (2009) Trees and networks before and after Darwin. Biology Direct 4: 43.

Reif, W.-E. (1983) Hilgendorf's (1863) dissertation on the Steinheim planorbids (Gastropoda; Miocene): the development of a phylogenetic research program for paleontology. Paläontologische Zeitschrift 57: 7–20.

Reif, W.-E. (1986) The search for a macroevolutionary theory in German paleontology. Journal of the History of Biology 19: 79-130.

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