RE: Lagosuchus/Marasuchus

["Tracy L. Ford" <dino.hunter@cox.net>]

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Fam
Jansma
Sent: Monday, April 29, 2002 8:00 AM
To: DML
Subject: Re: Lagosuchus/Marasuchus

You wrote:


>Could anyone advise me on the _Lagosuchus_/_Marasuchus _ situation, and
>the etymology of _Marasuchus_?
>
Lagosuchus=Marasuchus, although Sereno renamed the original type specimen
because it was supposedly lacking diagnostic characters. Partly due to the
bad condition the material is in. It is not that they are seperate genera of
some sorts. When the type material of Lagosuchus was found, it was in a very
bad state, a few years later there was another skeleton found of Lagosuchus
which is the one HP G.S. Paul used for his reconstruction, and this one was
in a more complete state. After studying both specimens, HP Paul Sereno came
to the above conclusion.
Marasuchus' etymology has probably come from the general area it was found
in, but I'll have to check.
>
>Would I be wrong to include _Lagosuchus_ in popular work with pictures
>(I suppose) based on _Marasuchus_?

>
No, that would be correct

Rutger Jansma

No, Lagosuchus does not mean Marasuchus. This is a common misconception.
Sereno et al named the REFERRED material and did not re-name the type
material (which you really can't do unless it's preoccupied). Lagosuchus IS
a valid and separate genus. (also see the archives as this has been
mentioned years ago also).

Genus: Lagosuchus ROMER, 1971
Etymology: Lagos (Greek), rabbit, Souchos (Greek), crocodile.

Species: talampayensis ROMER, 1971
Etymology:

Holotype: UPLR 09, (La Plata Museum No. 64-XI-14-11)

Locality: Southwest part of the Los Chanares locality, "2 km north of the
mouth of Rio Chanares," more accurately located 3 km north of the north
branch of the Chanares River and 5 km southwest of the Puerta de Talampaya,
La Rioja Province, Argentina.

Horizon: Los Chanares Formation.

Biostratigraphy:

Age: Ladinian Stage, Upper Mid Triassic Epoch, Late Triassic.

Material: Left scapulacoracoid, femur, tibia, fibula, and most of pes, and
dorsal vertebrae.

Note: Found in a block with the type of Gracilisuchus stipanicicorum.

Referred material:

ROMER, 1972

MCZ 4116

Material: Femur, articulated with which is the proximal end of a tibia, a
series of dorsal vertebrae, fragmentary remains of the pelvis.

Tucuman collections,

Number?: A hind leg.


ROMER, 1972

Instituto Lillo

Locality: Chanares beds, La Rioja Province, Argentina.

Horizon: Los Chanares Formation.

Biostratigraphy:

Age: Ladinian Stage, Upper Mid Triassic Epoch, Late Triassic.

Material: Complete left leg, 2 sacrals, ribs, and caudals.

BONAPARTE, 1975

PVL 3870: Very back of skull, posterior part of premaxilla, maxilla, 9
cervicals, 11 dorsal vertebrae, ilia, pubi, ischia, femur, tibia, fibula,
metatarsals, phalanges.

PVL 3871: Scapula and coracoid, humerus, ulna radius, femur.


Genus: Marasuchus SERENO & ARCUCCI, 1994
Etymology: Generic name refers to the mara, or Patagonian cavy (Dolichotis),
a solitarily cavimorph rodent that is quite abundant on the plains of the
Camp de Talampaya and around the type locality. The mara, which commonly
moves with a totting (four-legged, bouncing) gait, closely resembles
long-legged rabbits and hares. The name Marasuchus (mara; souchos (Greek),
crocodile) thus retains the spirit of Romer's original genus Lagosuchus
(lagos (Creek) Rabbit; souchos (Greek), crocodile).

Species: lilloensis SERENO & ARCUCCI, 1994
= Lagosuchus lilloensis ROMER, 1972

Holotype: PVL 3872

Locality: "area de Los Chanares, 2 km al SE de la Puerta de Talampaya.",
more accurately located 3 km north of the north branch of Chanares River and
5 km southwest of the Puerta de Talampaya, Chanares beds, Province of La
Rioja, Argentina.

Horizon: Los Chanares Formation.

Biostratigraphy:

Age: Ladinian Stage, Upper Mid Triassic Epoch, Late Triassic.

Material: Back of skull, complete left leg except for phalanges, complete
right leg, a series of vertebrae including sacrum and caudal vertebrae.

Tracy L. Ford
P. O. Box 1171
Poway Ca  92074