Ichnogenus Anchisauripus Lull
Ornithichnites (in part) E. Hitchcock 1841, p. 486
Eubrontes (in part) E. Hitchcock 1845, p. 23
Brontozoum (in part) E. Hitchcock 1847, p. 50
Anchisauripus Lull 1904, p. 486; 1915, p. 181; 1953, p. 166
Anchisauripus Olsen et al. 1998, p. 592, Fig. 12B.

Type ichnospecies: Anchisauripus sillimani (Figs., A, B, below).

Discussion: Anchisauripus is presently believed by us to be a nomen dubium because it was founded on inderminate material.

Anchisauripus sillimani

Ichnospecies Anchisauripus sillimani (E. Hitchcock)
Ornithichnites tuberosus (in part) E. Hitchcock 1841, p. 486, Pl. 37, Fig. 21.
Ornithichnites tuberosus (in part) E. Hitchcock 1843, p. 256 (check)
Ornithichnites sillimani E. Hitchcock 1843, p. 255.
Eubrontes dananus E. Hitchcock 1845, p. 23.
Brontozoum sillimani E. Hitchcock 1847, p. 49.
Brontozoum sillimanium E. Hitchcock 1848, p. 49.
Anchisauripus dananus Lull 1904, p. 288.
Anchisauripus sillimani Lull 1915, p. 181.
Anchisauripus dananus Lull 1953, p. 168.
Grallator( Anchisauripus) sillimani Olsen et al. 1992, p. 507, Fig. 12B.
Anchisauripus sillimani Olsen et al. 1998, p. 592, Fig. 12B

Lectoholotype: AC 4/6 (23/13 of E. Hitchcock, 1858; old No. 48) natural mold in gray siltstone from Chicopee Falls, Massachusetts, Portland Formation, collected prior to 1841 (Figs. A, B, right).

Discussion: Originally figured as part of the type series of the second ichnospecies named and described by E. Hitchcock (1836), Ornithichnites tuberosus (his Figs. 2, 5, unnumbered figure). However, Hitchcock in 1843 (p. 224) noted in reference to his paper of 1836 that, "A moment's inspection of these figures shows a striking difference between Fig. 20 of Plate 37 and the other two figures [21 of Pl. 37 and 22 of Pl. 38]. But as the former was destitute of claws, I thought it was safest not to separate it from the others. Having since, however, found the claws on numerous specimens, I shall describe this variety as the O. tuberosus; excluding the other figures above referred to." After describing O. tuberosus, based on Pl. 37, Fig. 20 of his paper of 1841 and new specimens, Hitchcock writes, "The variety of O. tuberosus ... differs so much from the other varieties given in Plate 37, figure 21, and Plate 38, figure 22. that I hesitate not to describe the latter as a distinct species. ... This new species which I found upon the figures of my Report, I propose to denominate O. sillimani, as a testimony of my respect for the character and the valuable and long continued labors of Professor Silliman in the cause of science." (p. 255). Thus, AC 4/6 and 35/31 become the type series of O. sillimani (pointed out to P.E.O. by Donald Baird, pers. comm., 1975; Olsen, 1980). No specific designation of a holotype was given, but because AC 4/6 (B, right) is a deeper and clearer impression it was designated as the lectoholotype of O.sillimani by Olsen et al. (1998). Ornithichnites sillimani again appears in Hitchcock's classification of footprints of 1844 (p. 317).

A, Ornithichnites sillimani
of Hitchcock (1841, Pl. 37,
Fig. 21). Modified from 
Olsen et al. (1998, Fig. 12A).
B, AC 4/6, the lectoholotype
of Anchisauripus sillimani.
Modified from Olsen et al.
(1998, Fig. 12B)
C, second O. sillimani
of Hitchcock (1841, Pl. 38,
Fig. 22). Modified from 
Olsen et al. (1998, Fig. 12E)
D, AC 35/31, second of the
original type series of
O. sillimani. Modified from 
Olsen et al. (1998, Fig. 12F)

The lectoholotype of A. sillimani (AC 4/6) is a natural mold with indistinct pad impressions. It is an underprint from close to the actual layer trod upon. There are a few breaks in the rock that impinge on the morphology of the track, especially posteriorly.

In the Anonymous post-1865 "Synopsis" of the ichnogenera and ichnospecies in the Hitchcock collection, AC 9/14 (from Middletown, Connecticut) is listed as the type specimen of Brontozoum sillimanium. Presumably this citation is what led Lull (1904) to list AC 9/14 as the type specimen of the type ichnospecies of his new ichnogenus Anchisauripus,although he gives it as Anchisauripus dananus rather than A. sillimani, which has priority. Lull (1915, 1953) later corrects this error in the specific epithet and refers to the correct prior synonym. Clearly the holotype of A. sillimani must be AC 4/6 not the more famous AC 9/14, because the latter was not discovered until many years after the former.

Conclusion: By the standards we have been applying to tetrapod ichnotaxa, we feel that both AC 4/6 and AC 35/31 are in fact indeterminate. Most of the pads are indistinct and there is even some question of which foot is represented by the tracks. Therefore, the species name Anchisauripus sillimaniHitchcock 1841 and the genus name Anchisauripus Lull 1904 are nomina dubia. The genus name Anchisauripus, thus should not be used, because biologically meaningful comparisions to the type specimen can not be made.