Pseudaetobatus belli, Cicimurri & Ebersole, 2015
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publication ID |
https://doi.org/ 10.26879/524 |
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publication LSID |
lsid:zoobank.org:pub:71918C81-C8B4-4B5F-B70E-AEF74647581 |
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persistent identifier |
https://treatment.plazi.org/id/EFBD51F0-301D-4934-826B-4277524A0C86 |
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taxon LSID |
lsid:zoobank.org:act:EFBD51F0-301D-4934-826B-4277524A0C86 |
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treatment provided by |
Felipe |
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scientific name |
Pseudaetobatus belli |
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sp. nov. |
Pseudaetobatus belli sp. nov.
Figures 4-5 View FIGURE 4 View FIGURE 5
zoobank.org/ EFBD51F0-301D-4934-826B-4277524A0C86
Etymology. Species named for Gorden L. Bell, Jr. in honor of his contributions to Alabama vertebrate paleontology. Gorden also collected the matrix sample from which this new species was recovered.
Hypodigm. MSC 35048 (holotype), lower median tooth ( Figure 4.1 View FIGURE 4 ); MSC 35054 (paratype), lower right distal-most lateral tooth ( Figure 4.2 View FIGURE 4 ); MSC 35058 (paratype), right half of upper? median tooth ( Figure 4.5 View FIGURE 4 ), MSC 35059 (paratype), upper right distal-most lateral tooth ( Figure 4.3 View FIGURE 4 ); MSC 35062
(paratype), intermediate lateral tooth ( Figure 4.4 View FIGURE 4 ). All Tallahatta Formation, site ADl-1.
Type locality. Site ADl-1, 31.317309 N, - 85.71598 W (N 31° 19’ 02” lat., W 85° 42’ 57” long.), Dale County, Alabama GoogleMaps .
Type horizon. Lower Tallahatta Formation, just above the “Meridian Sand Member equivalent” beds.
Additional material. Site ABu-3; 31.575983 N, - 86.738533 W; Butler County, AL; Hatchetigbee Formation (NP 11) – MSC 12692, distal part of upper left median tooth; MSC 12695, median tooth fragment; MSC 35083, 13 tooth fragments; MSC 35078, distal end of median tooth ( Figure 5.2 View FIGURE 5 ). Site AWa-1; 31.658767 N, - 88.091680 W; Washington County, AL; Hatchetigbee Formation (NP 11) – MSC 12699.1, left half of upper median tooth ( Figure 5.1 View FIGURE 5 ); MSC 12699.2, median tooth fragment; MSC 12670, fragments of three median teeth; MSC 12672, distal end of median tooth. Whynot Locality ; 32.275506 N, - 88.470072 W; Lauderdale County, MS; Hatchetigbee Formation (NP 11) – MSC 12756, distal end of median tooth; MSC 12776, distal-most lateral tooth ( Figure 5.9 View FIGURE 5 ). Site ADl-1; Dale County, AL, Meridian Sand Member; Tallahatta Formation (NP 12) – MSC 35079, right half of lower median tooth ( Figure 5.13 View FIGURE 5 ); MSC 35080, half of lower median tooth ( Figure 5.10 View FIGURE 5 ); MSC 35081, half of median tooth ( Figure 5.4 View FIGURE 5 ); MSC 35082, half of median tooth. Site ADl-1; Dale County , AL; Tallahatta Formation (NP 13) – MSC 35049, small lower median tooth ( Figure 5.5 View FIGURE 5 ); MSC 35050, small lower median tooth ( Figure 5.7 View FIGURE 5 ); MSC 35051, right half of large lower median tooth; MSC 35052, left half of large lower median tooth ( Figure 5.15 View FIGURE 5 ); MSC 35053, middle portion of lower median tooth; MSC 35055 lower right distal-most lateral tooth ( Figure 5.3 View FIGURE 5 ); MSC 35056, lower right distal-most lateral tooth ( Figure 5.11 View FIGURE 5 ); MSC 35057, two distal-most lower lateral teeth; MSC 35060, upper right distal-most lateral tooth ( Figure 5.12 View FIGURE 5 ); MSC 35061, upper right distal-most lateral tooth ( Figure 5.8 View FIGURE 5 ); MSC 35063, 13 median tooth fragments; MSC 35064, 123 median tooth fragments; MSC 35065, incomplete lower median tooth ( Figure 5.14 View FIGURE 5 ); MSC 35066 incomplete lower median tooth; MSC 35067, incomplete lower median tooth; MSC 35068, incomplete lower median tooth; MSC 35069, incomplete lower median tooth; MSC 35070, incomplete lower median tooth; MSC 35071, left side of lower median tooth ( Figure 5.6 View FIGURE 5 ); MSC 35072, upper median tooth (probably from leading edge of dentition); MSC 35073, left half of upper median tooth; MSC 35074, left half of upper median tooth; MSC 35075, left half of upper median tooth .
Diagnosis. Teeth are larger than those of the type species, Pseudaetobatus casieri . As in P. casieri , upper median teeth fairly straight, whereas lower median teeth are arcuate, both have crowns with rectangular cross sections, angular distal ends and labial/lingual ornamentation of fine vertical ridges; tooth base thick, with sharply oblique labial face and lingual lobes that extend distally past the crown foot. Distal-most lateral teeth differ from P. casieri in being less wide, with shorter and less pronounced distal projection, but more sharply basally curved margin. Intermediate lateral tooth morphology is six-sided and nearly symmetrical.
Description. The holotype is arcuate (labial edge convex, lingual edge concave) and measures 3.2 cm in width ( Figure 4.1 View FIGURE 4 ). Maximum labio-lingual dimension of the occlusal surface (at the middle of the crown) measures 0.7 cm, but each side of the crown tapers slightly distally and terminates at an angular margin (see also Figure 5.2, 5.6-7, 5.13 View FIGURE 5 View FIGURE 6 View FIGURE 7 ). The crown of this specimen is only 0.2 cm thick, but other median teeth in the sample (i.e., Figure 5.4 and 5.6 View FIGURE 5 ) show that the crown can be at least up to 0.4 cm in thickness. Other specimens have a crown that is nearly indistinguishable from the root, and we attribute these differences in crown height to in vivo wear. In transverse section the crown has an angular, slightly rectangular outline. Preserved ornamentation on the lingual crown face consists of fine wrinkling, and a thick, rounded transverse ridge is located at the crown foot. This ridge extends along the entire lingual edge of the crown, and its profile is enhanced by super- and subjacent parallel furrows. A shallow groove extending along the entire labial face of the tooth delineates the crown from the root. The root is thick (nearly 0.4 cm), polyaulocorhizous, and extends conspicuously distally past the crown, with the oblique labial face bearing numerous short transverse furrows that nearly intersect with lamellae located on the flat basal attachment surface. An additional median tooth morphology, represented by specimens like MSC 35058 ( Figure 4.5 View FIGURE 4 ), MSC 35073, and MSC 35074, differs from the above morphotype only in being straighter (i.e., less arcuate).
Three lateral tooth morphologies are attributed to this species. MSC 35062 ( Figure 4.4 View FIGURE 4 ) has a six-sided, nearly symmetrical crown, with the rather straight sides meeting at sharp angles. The distal side is thin and the distal angle, which still bears some smooth enameloid, curls slightly basally. A second morphology, represented by specimens like MSC 35054 ( Figure 4.2 View FIGURE 4 ; also Figure 5.3, 5.11 View FIGURE 5 ), has a crown that is slightly longer than wide, with an angular mesial margin. The distal margin is unusual in that it curls basally and terminates lingually into a short, pointed projection. This projection varies in length among the available specimens. The mesial part of the occlusal surface is worn (in vivo usage) but the distal part still bears smooth enameloid. The third morphology, characterized by specimens like MSC 35059 ( Figure 4.3 View FIGURE 4 ; also Figure 5.8 View FIGURE 5 -9, 5.12), has a crown that is wider than long. The mesial margin is angular, and the mesial three fourths of the occlusal surface is worn (in vivo usage). The remaining portion of the crown curls slightly basally and still bears smooth enameloid. The distal edge is straight and perpendicular to the crown’s width, and it terminates lingually into a pointed projection. The development of this projection varies among the three specimens available.
Remarks. With the exception of MSC 35062, the tooth morphologies described above very closely match specimens from Morocco that Cappetta (1986) identified and illustrated as Pseudaetobatus (pl. 3, figs. 9-12; pl. 4, figs. 1-4). According to his positional determinations, MSC 35048 ( Figure 4.1 View FIGURE 4 ) and others like it ( Figure 5.5-7, 5.13 View FIGURE 5 View FIGURE 6 View FIGURE 7 -15) are lower median teeth, MSC 350658 ( Figure 4.5 View FIGURE 4 ; also Figure 5.1 View FIGURE 5 ) is an upper median tooth, MSC 35054 ( Figure 4.2 View FIGURE 4 ; also Figure 5.3, 5.11 View FIGURE 5 ) is a lower lateral tooth at the margin of the dentition, and MSC 35059 ( Figure 4.3 View FIGURE 4 ; also Figure 5.8, 5.12 View FIGURE 5 ) is an equivalent tooth from the upper dentition. In contrast to MSC 35054 and MSC 35059, the crown morphology of MSC 35062 ( Figure 4.4 View FIGURE 4 ) suggests that this tooth articulated with other teeth on both the mesial and distal sides, and it would therefore represent an intermediate lateral tooth row located between the median tooth row and the distal-most lateral row at the edge of the dentition. This morphology was not identified in the type species, P. casieri ( Cappetta, 1986) , but we associate it with P. belli sp. nov. because of its similarity to the other lateral tooth morphologies attributed to this species.
The holotype of Pseudaetobatus belli sp. nov., a lower median tooth, is 20% larger than equivalent teeth of P. casieri illustrated by Cappetta (1986, plate 3, figure 9). In addition, the distal-most lateral teeth of P. belli sp. nov. are not as wide as those of P. casieri , the distal corner of the crown is not as elongated, but the distal edge is more tightly curled. The intermediate lateral tooth morphology represented by MSC 35602 may not have been available to Cappetta (1986) for his description of P. casieri , but it was likely present because it has been identified in another new species of Pseudaetobatus from South Carolina.
Stratigraphic and geographic range. Hatchetigbee Formation (NP 11) of eastern Mississippi and southern Alabama; Tallahatta Formation (NP 12- 13) of southern Alabama.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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