| Basic info | Taxonomic history | Classification | Included Taxa |
| Morphology | Ecology and taphonomy | External Literature Search | Age range and collections |
Heliscomys walshi
Taxonomy
Heliscomys walshi was named by Kelly (2009). Its type specimen is LACM 153717, a tooth (lower p4), and it is a 3D body fossil. Its type locality is Simi Valley Landfill, which is in a Duchesnean terrestrial horizon in the Sespe Formation of California.
Synonymy list
| Year | Name and author |
|---|---|
| 2009 | Heliscomys walshi Kelly p. 68 figs. 1, 2 |
Is something missing? Join the Paleobiology Database and enter the data
|
|
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Heliscomys walshi Kelly 2009
show all | hide all
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| T. S. Kelly 2009 | Heliscomys walshi differs from all other species of Heliscomys by having the following: 1) large, well-developed paracone always present on P4 (equal in size to protocone); 2) P4 entostyle lacking; 3) M1-2 preprotocrista and postprotocrista present with latter moderately-developed and extending posterolabially across central valley between protoloph and metaloph; 4) p4 (or dp4) and m1-2 with anterolingually directed lophid present on hypoconid that crosses and interrupts middle central valley between metalophid and hypolophid; and 5) m1-2 stylar cusps (protostylid and hypostylid) usually less developed. Two subgenera of Heliscomys are recognized (Syphyriomys and Heliscomys), which are
differentiated primarily by the size of P4 relative to that of M1 (Korth, 1995). H. walshi differs from species of Heliscomys (Syphyriomys) including H. (S.) gregoryi Wood, 1933, H. (S.) hatcheri Wood, 1935, H. (S.) subtilus (Lindsay, 1972), H. (S.) ostranderi Korth et al., 1991, and H. (S.) macdonaldi Korth and Branchiforte, 2007, by having P4 more reduced relative to M1-2 (mean P4 transverse width = 71% of mean M1-2 transverse width). It differs from species of Heliscomys (Heliscomys), including H. (H.) vetus (= H. senex Wood, 1935; but also see Korth, 1989; Bell, 2004; and Flynn et al., 2008), H. (H.) medius Korth, 2007a, and Megaheliscomys mcgrewi (= H. (H.) mcgrewi of Korth, 1989; also see Korth, 2007b) by having P4 less reduced relative to M1-2. Further differs from H. vetus, H. ostranderi, and H. subtilus by slightly smaller size, from H. hatcheri, H. gregoryi, H. macdonldi, and H. medius by smaller size, and M. mcgrewi by much smaller size. Further differs from H. ostranderi by having following: 1) when P4 paracone present in H. ostranderi, P4 paracone of H. walshi larger and much better developed; 2) p4 (or dp4) proportionately larger in size relative to m1-2; and 3) the p4 (or dp4) metaconid and protostylid are much better developed (relatively larger). Further differs from Megheliscomys mcgrewi by having P4 with much better developed cusps, including large paracone. It differs from Passaliscomys priscus Korth and Eaton, 2004, by having the following: 1) P4 paracone and protocone bases not as well separated, somewhat fused; 2) M1-2 hypostyle variably present; 3) M1-2 postprotocrista present that crosses and interrupts the central valley between the protoloph and metaloph; 4) M3 protocone and preprotocrista better developed; 5) m1-2 protostylids and hypostylids usually present; 6) m1-2 with anterolingually directed lophid present on hypoconid that crosses and interrupts middle central valley between metalophid and hypolophid; 7) m3 hypolophid more reduced relative to those of m1-2; and 8) smaller size. |
Measurements
No measurements are available
|
|
||||
|
|
||||
|
|
||||
|
|
||||
| Source: o = order, subc = subclass, c = class, subp = subphylum | |||||
| References: Carroll 1988, Lillegraven 1979, Ji et al. 2002, Hendy et al. 2009, Nowak 1999 | |||||
Age range: Duchesnean or 39.70000 to 37.00000 Ma
Collections: one only
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Duchesnean | USA (California) | Heliscomys sp. (type locality: 16813) |