Diagnosis:

Pleurodires with pelvis sutured to carapace and plastron, xiphiplastral notch, and cervical scale; complete series of eight neurals reaching two suprapygals; mesoplastra wider than long and not meeting in midline; differing from all other pleurodires in having very wide costovertebral tunnel (except Chelus), articulation tubercle on anterior edge of first thoracic rib, and shell shape with anterior edge wide and straight; posterior sides tapering with straight margin; neurals alternating in size, as in Dortoka; hyoplastral-hypoplastral fontanelle present; first thoracic rib nearly as large as second thoracic rib; thoracic vertebral centra flat ventrally, thoracic ribs flat and broad without ventral keel; first thoracic central articulation concave, wider than high; thoracic ribs 9, 10, and 11 forming sacrum and attaching to ilium.

Distribution:

The family extends from the Oxfordian of Cuba as the oldest to the Valanginian of Colombia as the youngest. The Oxfordian Notoemys “orig. Caribemys” oxfordiensis is about 156 mya, the Kimmeridgian central European Platychelys oberndorferi is about 152 mya, the Tithonian Argentinian Notoemys laticentralis is about 145 mya, and the youngest is the Valanginian Colombian Notoemys zapatocaensis, n.sp., about 135 mya (F. Etayo, personal commun.).

The geographical distribution for the revised family is extensive, but a late Jurassic paleogeography (Smith and Biden, 1977) shows a much closer association of these localities than a modern map (fig. 2). They all occur in marine, micritic limestones that seem to have been deposited in similar environments. Whether or not the shallow sea of Switzerland and Germany was continuous during the late Jurassic and early Cretaceous with the one in Cuba, Colombia, and Argentina is not clear, but seems possible.

Type Species:

Notoemys laticentralis Cattoi and Freiburg, 1961.

Included Species:

laticentralis, oxfordiensis, zapatocaensis.

Revised Diagnosis:

Pleurodiran turtle, having the sutured pelvis and xiphiplastral notch characteristic of pleurodires; carapace shape consisting of a wide, straight anterior shell margin, anterior carapace sides roughly parallel, and posterior sides tapering, similar to that in Platychelys but distinct from Proterochersis, Dortoka, Chelidae, and Pelomedusoides; differs from Proterochersis in having a low shell, no carapacial anal excavation, and fewer than 14 marginal scales; differs from Platychelys in having no supramarginal scales, wide cervical scale, smooth shell with no high protuberances or strong radiating ridges, relatively flat shell, and large suprapygal one; differs from Dortoka in having wide neurals and cordiform rather than oval shell.

Type Specimen:

IPN 15-EAC 140120031, a carapace and posterior part of plastron.

Type Locality:

El Caucho farm (73°15′W–6°49′N), northeast of Ciudad de Zapatoca, Department of Santander, Colombia.

Horizon:

Upper part of Rosablanca Fm (Guzman, 1985), late Valanginian based on ammonoid Synoceras verrucosum (F. Etayo, personal commun.).

Diagnosis:

A species of Notoemys (see table 1) that differs from N. laticentralis and N. oxfordiensis in having a first costal not contacting peripheral 3, peripheral 3 very small, and marginal scale 3 small and restricted entirely to peripheral 2, marginal 4 reaching peripheral 2; differs from N. laticentralis in having a slightly serrated rather than smooth posterior carapace edge, a notched pygal, narrower vertebral scales, and slight rather than no doming along posterior edge of pleural and vertebral scale areas.

Nuchal:

The right half of the nuchal bone (figs. 3, 4, 5) is preserved; it is missing its posterior margin, but retains the contact with the first peripheral. Most of its size and shape can be determined by flipping right to left. The nuchal of Notoemys zapatocaensis is nearly identical to that in Notoemys laticentralis and to what is known of the nuchal in Notoemys oxfordiensis.

Costals:

There are the usual eight costals (figs. 3–6) in IPN 15-EAC 140120031. Costals 5 to 8 are complete on both sides; costals 2 to 4 are best preserved on the left side and are missing only the lateral margins. Costal 1 is preserved laterally on the right side and medially on the left, but it is missing its anteromedial edge. The first costal in N. zapatocaensis (figs. 3, 6) is very similar to that bone in N. laticentralis. However, N. zapatocaensis differs from N. laticentralis and from most turtles in having an anterior contact only with peripherals 1 and 2 and not with peripheral 3. This condition is the same on both sides. It is possible that there is a suture in the crack between what we interpret as the two pieces of peripheral 1 (see fig. 3), but this seems unlikely when the pieces are placed using the left side and the ventral surface features as landmarks. Costal 1 has the normal pleurodire shape: anterior margin convex, posterior margin transverse, both meeting laterally in a point.

The first and second costals in N. zapatocaensis differ from N. laticentralis in the neural contacts. On the right side the second costal of N. zapatocaensis does not contact the first neural, and on the left side the contact is very small if present. In N. laticentralis the contact is more extensive. The first costal has a very small contact with the second neural in N. zapatocaensis, while in N. laticentralis there is a wider first neural/second costal contact. Costal 5 in N. zapatocaensis has a contact with the sixth neural, absent in one specimen of N. laticentralis, MOZP 2487, but present in the type specimen. The contacts of the other costals are the same in N. zapatocaensis and N. laticentralis.

On the ventral surface (figs. 7, 8), the first costal in N. zapatocaensis shows the axillary buttress of the hyoplastron reaching onto the lateral third of the costal, where an elongate pit is present on the adjacent peripherals as well as the first costal, for the buttress articulation. The medial extent of the buttress may be slightly more in N. zapatocaensis than in N. laticentralis.

The first thoracic rib is preserved in IPN 15-EAC 140120031, but it is damaged laterally on both sides. The rib is large, compared to living pleurodires, but it is not as large as in Proganochelys. The first thoracic rib in N. zapatocaensis is broad and flat, as are the other thoracic ribs. In N. laticentralis the first thoracic rib is smaller than in N. zapatocaensis, but it is still larger than in living pleurodires. The remaining ribs in N. zapatocaensis (figs. 7, 8) are flat and broad medially, narrowing strongly at the point of costal attachment, as in N. laticentralis and Platychelys. The costovertebral tunnel formed between the thoracic neural spine and the costal attachment is very large in N. zapatocaensis, N. laticentralis, and Platychelys, significantly larger than in Proganochelys and all other pleurodires except Chelus. On the anterior margin of the first thoracic rib in N. zapatocaensis is a raised surface that appears to be an articulation facet, possibly for the scapula. This raised tubercle also occurs in N. laticentralis and Platychelys, but not in Proganochelys or living pleurodires. It is indeterminate in N. oxfordiensis.

Peripherals:

The first peripheral (figs. 4, 6) in Notoemys zapatocaensis has a narrow medial edge, where it contacts the nuchal, and a wider lateral contact with the first costal, similar to that in Notoemys laticentralis. However, beginning with the second peripheral, N. zapatocaensis shows a distinct difference from N. laticentralis and Platychelys, as well as most other turtles (fig. 5). Peripheral 2 is relatively large, larger than in N. laticentralis, and extends laterally to contact costal 2, a condition absent in N. laticentralis, Platychelys, and other pleurodires. It is unlikely that this is a pathology, as it is the same on both sides. It is probably related to a small triangular ossification, at the anterior end of the suture between peripheral 2 and the peripheral posterolateral to it. It is probable that this small ossification is actually peripheral 3, greatly reduced and squeezed out toward the edge of the shell. This is not certain, but N. zapatocaensis has one less pair of peripherals than other specimens of Notoemys if this small ossification is not a peripheral. However, the peripherals articulating with costals 2 and 3 are missing, so the number of peripherals cannot be determined by direct count. The remaining peripherals that are present (fig. 6), on costals 4 to the pygal, are in the same positions as peripherals in N. laticentralis, so it is likely that the missing peripherals were also consistent with N. laticentralis. If this is the case, then N. zapatocaensis would only have 10 pairs of peripherals articulating with costals. Another feature supporting the identification of the small ossification as peripheral 3 is that marginal 3, usually extending onto peripheral 3, is a small scale entirely on peripheral 2, just medial to the small ossification.

To make comparison easier, we assume that the above hypothesis concerning peripheral 3 is correct, so that the remaining peripherals in N. zapatocaensis are numbered the same as in N. laticentralis (fig. 6). A fragment of peripheral 6 is present on the left side along with a complete peripheral 7 (fig. 4). Peripherals 8 to 11 are present on both sides. These peripherals in N. zapatocaensis are very similar to those in N. laticentralis in size and shape and have the same contacts. The only nearly complete bridge peripheral remaining is 7. It is like N. laticentralis in having a relatively small ventromedial plate with the hypoplastron making up most of the ventral plate of the bridge (fig. 8). In both N. zapatocaensis and N. laticentralis, as well as N. oxfordiensis, the hypoplastron contact is not a tight suture but seems to be at least partially ligamentous, with a few pits on peripheral 7 for processes on the hypoplastron. Peripherals 8 to 11 have a low ridge marking the edge of the body wall attachment that parallels the edge of the shell. As in N. laticentralis, this ridge in N. zapatocaensis lies close to the shell margin, so that there is little overhang of the peripherals.

Neurals:

There are eight neurals in Notoemys zapatocaensis (fig. 6), forming a complete series from nuchal to suprapygal, as in Notoemys laticentralis and Platychelys. Neural 1 has a broken edge anteriorly so its complete extent is not known, but its sides are roughly parallel as in Platychelys, differing from the anteriorly tapering sides of N. laticentralis and N. oxfordiensis. The remaining neurals are complete. They form a series, very similar to that in N. laticentralis and N. oxfordiensis, and to a lesser extent, in Platychelys. The pattern is characterized by roughly alternating large and small neurals, with some asymmetry. The first neural in N. zapatocaensis is larger than the second, as in N. laticentralis, N. oxfordiensis, and Platychelys. In N. zapatocaensis neural 1 does not contact costal 2 (or the contact is very small, as the sides are asymmetrical), in contrast to these taxa. Neural 2 is four-sided, wider than long, as in N. laticentralis, N. oxfordiensis, and Platychelys. Neural 3 is six-sided, contacting costals 2, 3, and on the left side only, costal 4. This same asymmetry is seen in the specimen of Platychelys figured by Lapparent de Broin (2001: fig. 1), and a similar asymmetry is in the type specimen of N. laticentralis but there is a costal 4 contact on both sides. Neural 4 is smaller than neural 3 in N. zapatocaensis, and contacts only costal 4, except at its anterolateral corner, where there is a costal 3 contact. This asymmetry also occurs in the Platychelys figured by Lapparent de Broin (2001: fig. 1), but N. laticentralis is symmetrical and lacks the costal 3 contact. N. oxfordiensis has a costal 3 contact on the left side.

Neural 5 is slightly larger than 4 in N. zapatocaensis, and contacts costals 4 and 5 as in N. oxfordiensis, N. laticentralis, and Platychelys. The type of N. laticentralis also has a costal 6 contact on the left side. Neural 6 in N. zapatocaensis is roughly six-sided, in contrast to the four-sided neurals 4 and 5, and its sides taper posteriorly rather than being parallel in all the anterior neurals. In N. laticentralis and Platychelys, neural 6 is parallel-sided. Neural 7 in Notoemys zapatocaensis is six-sided, almost twice as wide as long, and asymmetric, with its left side longer than the right. In N. laticentralis neural 7 is four-sided. Neural 7 in N. zapatocaensis has wide contacts with costals 6 and 7, while in N. laticentralis most of the neural contacts costal 6 and only a small contact is with costal 7. Neural 8 in N. zapatocaensis contacts costals 7 and 8 and suprapygal 1, as in N. laticentralis. It would seem that asymmetry in many carapace bones, particularly the neurals, is a consistent feature of Notoemys. It also seems to be common in Platychelys, and possibly Dortoka.

Thoracic Vertebrae:

Thoracic vertebrae 1 through 11 and the first caudal are preserved and completely visible (figs. 7, 8).

The first thoracic vertebra in Notoemys zapatocaensis has a concave central articulation that is wider than high, as in Platychelys. The first thoracic rib has a broad, sutured articulation with the anterior half of the centrum. The second thoracic rib has an angled articulation with the posterior third of the first thoracic centrum and also with the anterior part of the second thoracic centrum, also as in Platychelys. The first thoracic rib in N. zapatocaensis is nearly as large as the second thoracic rib (equals the first costal rib), with an oval fontanelle between them medially and a sutured contact more laterally. The first thoracic rib seems to end just before reaching the axillary buttress, also as in Platychelys. In N. zapatocaensis there is an articular protuberance on the anterior edge of the first thoracic, as in Platychelys. The second thoracic rib is large and flat on its ventral surface. The costovertebral tunnel is wide here, nearly reaching the axillary buttress. This width is maintained for the length of the shell at least to thoracic rib 8 (costal rib 7). This rib morphology also agrees with Notoemys laticentralis, and Platychelys.

Thoracic vertebrae 2 through 6 have a similar shape: rib articulation ankylosis anteriorly and posteriorly, with an indented waist between. Thoracic vertebra 7 has only the anterior facet and thoracic vertebra 8 is smaller than the others, with the rib attaching in its middle and no other facets. This differs from Platychelys, which has the eighth thoracic rib (equals costal rib 7) articulating on both thoracic centra 7 and 8. Thoracic ribs 9, 10, and 11 attach to the ilium as sacral ribs. Their centra are smaller than the more anterior centra.

The first caudal appears between the ilia in the same position as in Platychelys (Bräm, 1965). The anterior central articulation is convex, the posterior one concave. A sutured rib extends directly laterally from the centrum, and reaches the ilial shaft.

Suprapygals and Pygal:

Notoemys zapatocaensis (figs. 3, 4, 6) has two suprapygals and a pygal, as in Notoemys laticentralis and Platychelys. These are complete in IPN 15-EAC 140120031, except for breakage on the left side of suprapygal 2. The first suprapygal in N. zapatocaensis is four-sided, longer than wide, with parallel sides. N. laticentralis is also four-sided, but the sides taper anteriorly so the anterior length is about half its posterior length.

Suprapygal 2 in N. zapatocaensis is wider anteriorly than posteriorly, as in N. laticentralis, both apparently differing from Notoemys oxfordiensis, which is widest in the middle. Suprapygal 2 contacts the first suprapygal anteriorly, costal 8 anterolaterally, peripheral 11 posterolaterally, and the pygal posteriorly. The pygal contact in N. zapatocaensis is V-shaped posteriorly, rather than straight or curved as in N. laticentralis and N. oxfordiensis. In Platychelys suprapygal 2 differs from all Notoemys in being parallel-sided and much narrower.

The pygal in Notoemys zapatocaensis (fig. 6) has a deep indentation for the second suprapygal and is slightly notched on the midline at its posterior edge for the marginal 11 sulcus. N. laticentralis has no indented suture for the suprapygal, although a very slight notch seems to be present.

Cervical Scales and Vertebrals:

Notoemys zapatocaensis (fig. 6) has a short, wide cervical scale as in Notoemys laticentralis, wider than in Platychelys. The vertebral scales are very similar to those in Platychelys, differing from those in N. laticentralis, because vertebrals 2 and 3 are distinctly wider in N. zapatocaensis than in N. laticentralis. In N. zapatocaensis the scale sulcus lies about one-third the distance from neural to distal end of the costal; in N. laticentralis the sulcus is one-half or more of the distance to the lateral end of the costal. The lateral edges of the vertebrals in N. zapatocaensis are straighter than in N. laticentralis, in which they jut laterally where the pleurals meet.

Pleural Scales:

The four pairs of pleural scales in Notoemys zapatocaensis (fig. 6) are very similar to those in Notoemys laticentralis, except that they are wider due to the narrower vertebrals.

Marginal Scales:

The marginal scales in Notoemys zapatocaensis (fig. 6) show differences with those in Notoemys laticentralis. The first marginal lies on the nuchal and peripheral 1, as in N. laticentralis, and marginal 2 extends from peripheral 1 onto peripheral 2, as in N. laticentralis. Marginal 3, however, is a small, oval scale, lying on the edge of peripheral 2, and not extending onto peripheral 3. This may be related to the apparent reduction of peripheral 3, which seems to be a small ossification in the peripheral 2–peripheral 4 suture (see above). Marginal 4 barely extends onto peripheral 2, a condition not found in N. laticentralis, Platychelys, or other pleurodires, which have marginal 4 lying on peripherals 3 and 4. As in N. laticentralis and Platychelys, the anterior marginals are short and restricted to the edges of the peripherals and do not extend onto the costals.

Marginal 5 is not preserved; marginals 6 to 11 are very similar to those in N. laticentralis. The 8th and 10th marginals are five-sided rather than four-sided, as they extend medially along the sulci between pleurals. This is in both N. zapatocaensis and N. laticentralis (and seems to be in N. oxfordiensis), but not Platychelys. There are no supramarginals or anal/pygal scales in Notoemys, as occur in Platychelys.

Hypoplastron:

Most of the right and left hypoplastra are preserved (figs. 9, 10). The anterior margin shows the contact with the mesoplastron. Dorsomedially, the margin is broken, and the bone is thin, but there is no sign of a fontanelle. Medially, both hypoplastra meet on the midline. Posteromedially, both hypoplastra show a thin, natural edge, indicating a possible narrow fontanelle, just anterior to the xiphiplastron contact. The femoral–abdominal sulcus is not visible, although the area where it is usually located is present on both sides.

Xiphiplastron:

Most of both xiphiplastra are present (figs. 9, 10, 11), but broken along their medial edges, so there is no midline contact. There is no indication of a fontanelle on the xiphiplastron; the medial margins are all broken edges. On the ventral surface, there is a clear anal–femoral sulcus, with an indentation on the lateral xiphiplastron margin. The xiphiplastron narrows posteriorly and comes to a rounded margin, as in Platychelys. There is an anal notch, also as in Platychelys. Although Notoemys laticentralis is not well preserved in this area, what is known is entirely consistent with the Colombian xiphiplastron.

The pubic scar (fig. 11) is covered by the pubis on both sides, but it is clearly wide and relatively large, and reaches the lateral margin of the xiphiplastron, in contrast to podocnemidids and bothremydids. The ischiac scar is visible on the left side; the ischium is in contact on the right side. The ischiac scar is relatively large, reaching the lateral edge of the xiphiplastron. The scar is roughly triangular, but widens medially to reach the midline, in contrast to bothremydids and podocnemidids.

Ilium:

The ilium (fig. 8) is preserved on both sides, with thoracic ribs 9, 10, and 11 reaching it. These are very similar in position to those in Platychelys. The iliac articulation is on costals 7 and 8 in Notoemys zapatocaensis. It seems that the medial edge of peripherals 10 and 11 lie just against the ilium, so that the sutural scar does not quite reach the peripherals. The suprapygal is less clear, but it also does not seem to have the iliac scar on it, although this is not clear anteriorly. The ilium blade is elongate, without a lateral process seen in pelomedusids and podocnemidids. The ilium neck is shorter than it is in Pelomedusoides. The acetabulum shows the usual tripartite formation; it is best preserved on the right side. The articulation surface is wider and oval as in Platychelys, rather than more circular as in Pelomedusoides.

Pubis:

The right pubis is in articulation and nearly complete, although much is obscured by matrix. The anterior process is damaged on both sides and the shape of the pubic scar (fig. 11) can only be seen in a few places, but it is relatively wide, as in Platychelys, rather than narrow as in Pelomedusoides. The thyroid fenestra is poorly preserved, but enough can be seen to show that it was confluent and large as in Platychelys, not small as in Proganochelys. The pubis contact goes right to the edge of the xiphiplastron, as in Platychelys. It is not retracted from the edge as in Pelomedusoides.

Ischium:

Most of the right ischium is present, but its medial margin is missing. The ischium scar (fig. 11) is preserved on the left xiphiplastron and some of the left ischium can be articulated on it. The right ischium is disarticulated from the acetabulum and moved posterodorsally. The ischium of Notoemys has a wider shaft than in Pelomedusoides and its posterior process is more like a sheet of bone than a column.