Sivaonyx beyi, Peigné & Bonis & Likius & Mackaye & Vignaud & Brunet, 2008
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publication ID |
https://doi.org/ 10.1111/j.1096-3642.2008.00377.x |
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persistent identifier |
https://treatment.plazi.org/id/5B5587D3-FFDF-FFE7-DD71-FB22F88FFDB8 |
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treatment provided by |
Felipe |
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scientific name |
Sivaonyx beyi |
| status |
sp. nov. |
SIVAONYX BEYI SP. NOV.
Holotype: TM 171-01-033, partial skeleton of one individual including: fragment of left edentulous hemimandible, fragment of right hemimandible with distal root of p3, p4 (broken) and damaged m1, proximal fragment of left and right scapulae, subcomplete left humerus and two distal fragments of right humerus, proximal fragment of left ulna and complete right ulna, subcomplete left radius, proximal fragment of diaphysis of right radius, right scapholunar, left magnum, right Mc III, fragment of right Mc II, and left Mc I, II, III, fragments of undetermined metapodials, seven fragmentary caudal vertebrae (Cd 2, 4, 5, 7, 10, 11 and 12), fragment of left hip including acetabulum, left femur lacking distal epiphysis and diaphysis of right femur, left tibia lacking the proximal epiphysis and diaphysis of right tibia, left astragalus, left navicular, left Mt II and IV, incomplete right Mt II, III and IV, five proximal phalanges.
Type locality: TM 171, Toros-Menalla fossiliferous area, Chad; late Miocene.
Etymology: From ‘beyi’, meaning large in the Goran language.
Referred specimens: TM 31-99-001, distal fragment of right humerus; TM 74-99-015, left calcaneum; TM 90- 00-066, right M1; TM 172-05-001, subcomplete right hemimandible with damaged m1; TM 219-01-001, anterior fragment of mandible with canine root and p1-3 roots; TM 247-01-005, fragment of right hemimandible with m1; TM 355-02-002, fragment of left hemimandible with fragment of canine, p2-3 roots, fragment of p4, subcomplete m1.
Geographical and stratigraphical distributions: Chad: Toros-Menalla fossiliferous area ( TM 74, 90, 171, 172, 219, 247, 355), late Miocene (c. 7 Ma).
Diagnosis: Large species of Sivaonyx (c. 60 kg) with two lower incisors only, and in having a postcranial skeleton displaying only a few characters related to an aquatic adaptation.
Differential diagnosis: Differs from S. bathygnathus in being larger, which may be related to the presence of a much thicker and taller mandible, and in having a much more robust (L/W ratio lower) and shorter p4 compared with m1. Differs from S. soriae in its larger size, having only two lower incisors, an M1 that is transversely more elongated with a mesiodistally less extended lingual cingulum and more distantly located metacone and metaconule. Differs from S. hendeyi in having an m1 with a talonid that is wider than the trigonid and being less bunodont, which implies a deeper carnassial notch, smaller and less transversely orientated paraconid, shorter and more erect metaconid, and metaconid and protoconid proportionally taller relative to m1 length. Furthermore, the femur of S. hendeyi is more robust, has a thinner neck and a larger head that is more proximally orientated, less developed trochanters and less extended trochanteric fossa. Differs from S. africanus in having an M1 that is less robust, more transversely elongated with a less expanded lingual cingulum, a crest-like metaconule extending mesially, p4 longer relative to m1 length and a shorter and more erect metaconid on m1. Differs from S. ekecaman in having a less bunodont m1, which includes a greater elongation, a less robust and more erected metaconid, a shorter talonid, and a much more transversely elongated M1 with taller cusps, no parastyle, more developed paracone and a much more expanded lingual cingulum. Differs from S. kamuhangirei in its smaller size and by a more reduced and less transversely orientated paraconid on m1. Differs from Sivaonyx sp. from Wadi Natron in having a proportionally more elongated m1. The case of Sivaonyx senutae will be discussed below.
Description (Figures 1–7, Tables 1–5)
Mandible (Figs 1, 2, Table 1): The mandible is very stoutly built, with a thick, tall and curved corpus so that the hemimandibles are posteriorly diverging, as in Aonyx capensis . There are several mental foramina in variable positions below the premolars. In all of the specimens, the largest one is below the diastema between p3 and p 4 in the dorsal half of the corpus, while 3–6 additional foramina are present below p1 and p2. In the individuals that completely preserve the chin ( TM 355-02-002, Fig. 1E–G, TM 219-01-001), there is a distinct ventral apophysis prolongating the symphysis. The latter is deeply indented, dorsoventrally tall and anteroposteriorly short. Muscular attachments for the masticatory muscles (Mm. tem-
› Figure 1. Sivaonyx beyi sp. nov., photographs of the lower dentition. TM 171-01-033, holotype: fragmentary left hemimandible in A, lingual view, B, labial view, and fragmentary right hemimandible with subcomplete p4 and damaged m 1 in C, labial view and D, dorsal view. TM 355-02-002: fragmentary left hemimandible with fragment of p4, subcomplete m 1 in E, labial view, F, lingual view, and G, dorsal view. TM 172-05-001: subcomplete right hemimandible with damaged m 1 in H, labial view, I, lingual view, and J, dorsal view. TM 247-01-005: fragment of right hemimandible with m 1 in K, labial view, L, lingual view, and M, dorsal view. Scale bar = 10 mm.
·
poralis, masseter, zygomaticomandibularis and pterygoideus) are strongly developed. The attachments for the Mm. masseter and temporalis are particularly deep, suggesting great strength in these adductors during mastication, which may be related to a diet based on relatively hard items, as in Aonyx capensis . The masseteric fossa is deep and large, although anteriorly not reaching the level of m2; it is ventrally bounded by a strong and laterally projected masseteric ridge. This suggests a strong development of the M. masseter profundus and M. zygomaticomandibularis, the latter of which is regarded as a part of the former by some students ( Turnbull, 1970; Gorniak, 1986; Evans, 1993; Barone, 2000). Ventrolaterally to the masseteric ridge, the mandible surface is relatively flattened. This area, where the M. masseter superficialis inserts, is also particularly wide and elongated compared with that in other carnivorans, as it extends backwards to the angular process and forward to nearly below the anterior margin of the masseteric fossa. The coronoid process is incompletely preserved on the available material. The anterior rim of the process is nearly vertically orientated (i.e. nearly at right angles relative to the alveolar plane). A fragment of the tip of the process is preserved on the left hemimandible of the type. It is rather triangular-shaped and has a thin posterior rim, and an anteriorly thick dorsal rim; the tip also has a convex lateral side and a deeply excavated medial side for the attachment of the M. temporalis profundus. The attachment area for the deepest fibres of the M. temporalis profundus is also strongly marked on the medial side of the coronoid process. This area is delimited (1) ventrally, by a horizontal crest that runs from the mandibular condyle to the posteroventral corner of the m2 alveolus; (2) anteriorly, by an even stronger, roughly vertical crest located just posterior or posteroventral to the m2 alveolus. The ventral surface of the corpus is also marked by the attachment area of the M. digastricus. It is clearly distinct on TM 171-01-033, TM 172-05-001 and TM 355-02- 002 where it extends from slightly posterior to the mandibular foramen forward to at least beneath m1; the insertion is about 50 mm in total length. The lateral boundary of this insertion area is prominent and crest-like. This insertion is extended more medially than laterally; moreover, it narrows anteriorly and enlarges posteriorly, where it extends dorsally on the medial surface of the mandible. The elongation and extension of the M. digastricus insertion is rather similar to that in Enhydra lutris and unlike Lontra canadensis ( Scapino, 1976) . The tip of the angular process is not preserved, but it is likely that it was short. A large insertion area for the M. pterygoideus medialis is visible on the medial surface of the angular region, extending dorsally to the ventral rim of the condyle and anteriorly to a level about 1 cm posterior to the mandibular foramen.
Dentition (Figs 1, 2, Tables 2, 3): The dentition is poorly preserved in the material, with only p4 and m1 being nearly complete. The shape and location of the alveoli or roots of the other teeth provide some information, however. Two individuals ( TM 219-01- 001 and TM 172-05-001, Figs 1H–J, 2H–J) have only two lower incisors, with i1 presumably being absent as in Enhydra lutris ( Estes, 1980) . As in extant otters, the incisor alveoli are transversely compressed, that of i3 being larger and more labially located than that of i2. The anterior part of the chin is not preserved in TM 355-02-002 (Fig. 1E–G), but one incisor alveolus is visible along the symphyseal face. Given its location, this alveolus is that of i2, while that of i1 is probably absent. Only a fragment of the root and/or the base of the crown of the canine is available in some individuals ( TM 172-05-001, TM 355-02-002, TM 219-01-001). The tooth was large and the root poorly curved. The number of premolars is variable in the sample from Toros-Menalla. In TM 171-01-033 (Figs 1A–D, 2D–F) and TM 172-05- 001 p1 is absent and p2 is single-rooted. Nevertheless, the left hemimandible of the former displays evidence of alveolar resorption at the level of p1 and p2, which suggests these teeth may have fallen out during the animal’s life. TM 219-01-001 and TM 355- 02-002 both have a tiny p1 alveolus that is closely applied against, and partly coalescent with, the canine alveolus; in these individuals p2 had two nearly fused roots and was obliquely orientated, the mesial root being labial. In all of the available specimens the p3 was short and double-rooted. Its roots are preserved in TM 355-02-002, TM 172-05-001 and TM 171-01-033, being partly fused in the last two; the distal one is markedly larger than the mesial one and is mesiodistally compressed. The p4 is preserved on the right hemimandible of the holotype TM 171-01-33, though the main cuspid is broken off. The tooth is short and distally very wide; it was ·
Rank of caudal vertebrae probably taller than m1, judging by a comparison with other specimens preserving the latter (e.g. TM 247-01-005, Figs 1K–M, 2A–C). There is no mesial accessory cuspid, but a distal, incompletely preserved one was certainly well developed, closely appressed to the main cuspid, and labially placed. A prominent crest extends from the distolingual face of the main cuspid, as in, for example, Lutrogale perspicillata ( MNHN CG 1962-1646). The lower carnassial is nearly complete in TM 247-01-005, TM 355- 02-002 and TM 172-05-001. It is a low and wide tooth. The paraconid is only slightly lower than the protoconid and has a slightly backwardly orientated mesial face, a cingulid that may be marked (e.g. TM 355-02-002) and an almost transversely orientated distal face. Labially, the basal half of the distal face of the protoconid is occupied by a prominent vertical crest. The metaconid is a prominent cuspid that reaches approximately the same height as the protoconid; it is separated from the paraconid by a deep and wide V-shaped valley; it has a somewhat oblique distal face; it is slightly distal to the protoconid, from which it is separated by crests forming a V-shaped valley prolonged by a short notch. The talonid is long and wide, slightly wider than the trigonid; it is poorly basined and located mainly distally to the metaconid. All of the cuspids of the talonid are more or less worn in the available material. The hypoconid forms a large labial crest, which has a lingual slope that occupies more than one-half of the talonid width; it is separated from the distal crest of the protoconid by a small notch. The wear pattern of the talonid indicates that a small hypoconulid was probably present in TM 247-01-005, as was a small entoconid in TM 172-05-001, TM 355-02- 002 and TM 247-01-005. The cingulid is strongly developed only along the labial face (e.g. TM 247-01- 005), but it may extend on the lingual face of the paraconid (e.g. TM 355-02-002). The m2 alveolus is large, particularly in TM 355-02-002 (9.5 mm long and 5.5 mm wide), oval-shaped and lingually located; because this tooth is located at the base of the ascending branch, its alveolar plane is orientated almost anteriad in TM 172-05-001.
The single preserved upper tooth is an isolated M1 germ with unworn cusps ( TM 90-00-066; Fig. 2G, Table 3). The tooth is transversely elongated, the mesial and distal faces being approximately parallel. ·
The paracone and metacone are trenchant, the former being much longer but clearly lower than the latter. The protocone and paraconule form a mesially curved blade; both have a nearly vertical mesial face and are separated by a notch; the paraconule is slightly smaller than the protocone. There is a prominent metaconule located on the distal border, separated from the metacone by a V-shaped valley. There is no crest linking the metaconule and the protocone. The lingual cingulum is developed, extended somewhat distally, with a tilted-up rim. The cingulum is also present along the mesial and labial borders and is very wide labially to the paracone.
Postcranium ( Figs 3–7, Tables 4–6): Most of the available postcranial bones belong to one individual, TM- 171-01-033. Only a few vertebrae were preserved, but none completely. The only remaining element of the cervical, thoracic and lumbar vertebral segments is a small fragment that preserves the anterior and posterior articular processes and a part of the dorsal arch with the basis of the spinous process. The articular surfaces of both processes are orientated at about 45° relative to the sagittal axis, which may correspond to one of the last cervicals or the first thoracic vertebrae. Except for its large size, a detailed comparison with extant taxa is not possible. Seven caudal vertebrae are variably preserved ( Fig. 3A–P). It is possible to determine their position based on a comparison with extant otters ( P. brasiliensis , Lo. felina , Lu. lutra ). In Lu. lutra only the first eight or nine caudal vertebrae are complete, i.e. have transverse and spinous processes and a complete vertebral arch enclosing a long vertebral canal. Four of the caudal vertebrae preserved in TM- 171-01-033 display all or a part of these morphological traits. The three others are poorly preserved but certainly represent more posteriorly located vertebrae. The position of the caudal vertebrae can be determined using several morphological characters observed in extant species, of which only a few are available in the Chadian fossil otter. In extant otters, the length of the vertebral body (measured along the dorsal rim) increases from the first to the ninth or tenth vertebra depending on the species ( P. brasiliensis , Lu. lutra , Lo. felina are used here), but the length does not differ much from the ninth to the eleventh caudal. As the vertebral body lengthens, it also becomes smaller in diameter and the posterior section (which may be markedly dorsoventrally flattened in the first caudals) becomes more rounded. Furthermore, the posterior articular process becomes more reduced in size and less laterally projected, and the spinous process is present on the first six caudals only, then becomes reduced further posteriorly. Figure 4 View Figure 4 presents the hypothetical position of the preserved caudal vertebrae of TM- 171-01-033 based on their body length (Table 4) to fit the vertebral profile obtained from the extant species. Thus, given their shape and body length, we infer that the preserved caudal vertebrae of the Chadian species most probably represent the second, fourth, fifth, seventh, tenth, eleventh and twelfth ones. This ordering is consistent with the aforementioned characters, especially the diameter, size of the body, and development and lateral projection of the posterior articular processes. The second caudal vertebra ( Fig. 3A–C) consists of the posterior part of the body and most of the dorsal half. The body is short but wide, with a posterior part that is dorsoventrally flattened; the surface of the latter is convex externally but slightly depressed in its centre. The vertebral foramen is large and the vertebral canal is 17 mm long; its anterior opening is wider than high while this is the opposite for the posterior opening. The anterior articular process (or prezygapohysis) is large and thick; the articular surface is large, oval-shaped, anteroposteriorly elongated and strongly concave in its medium part. The mammillary process is not well preserved but was certainly small. The tip of the spinous process is not preserved; its anterior rim is thick and strongly backwardly orientated. The posterior articular process (or postzygapophysis) is much more reduced and less laterally projecting than the anterior one; it is oval, anteroposteriorly elongated, and its surface is flat to slightly convex, being ventrolaterally orientated. Transverse processes are not preserved. In comparison with the second one, the fourth caudal ( Fig. 3D–G) vertebra is better preserved, lacking only a part of its ventral half. It differs in having a longer body, and more reduced articular processes, with the posterior ones being much less laterally projecting, slightly larger mammillary processes, a thinner spinous process and a less dorsoventrally flattened anterior opening of the vertebral canal. The anterior face of the body, which is not preserved on the second caudal, is here rounded and its surface is similar to that of the ·
posterior face of the body: smooth, externally convex and centrally depressed. The transverse processes are not preserved; they are 7 mm thick at their posterior base. Most of the fifth caudal vertebra body, the vertebral canal and the dorsal arch are preserved ( Fig. 3H–J); articular and transverses processes are broken off. The shape and surface of the anterior and posterior articulation of the body are like those of the other caudals. On the ventral side of the anterior face, there are some fragments of a haemal arch (or chevron bone), which protects the median coccygeal artery; there is no visible suture between either side of the haemal arch and the body. The seventh caudal ( Fig. 3K–M) is represented by most of the body, a part of the dorsal arch and the vertebral canal, and most of the haemal arch. This vertebra differs from the preceding ones in having a longer but smallerdiameter body and a smaller but equally long vertebral canal. The haemal arch is well preserved and completely fused to the body. It is particularly long basally (extending about half of the length of the body) and is ventrally extended (nearly the height of the body). The two branches of the arch are transversely compressed, curved forward and tapering ventrad; their lateral surface is smooth and presents a low horizontal crest at mid-height. The three other caudal vertebrae are more fragmentary ( Fig. 3N–P); they retain only a part of the body, including the anterior and posterior face, and a small part of the vertebral and/or haemal arches. The body length of these caudals is greater than the more anterior ones while the diameter of their body is more reduced. In addition, the body length and diameter decrease from the tenth to the twelfth caudal.
Only the proximal extremity of both scapulas is preserved ( Fig. 3Q, R), including the glenoid fossa, the neck and a small portion of the scapular spine. The glenoid fossa is oval (L/W ratio of 0.69), piriform and anteriorly narrow, although less so than in ursids ( Davis, 1964: 91) and extant otters. The articular surface is excavated, with a moderately developed supraglenoid tubercle. A small, rounded, smooth and slightly concave area for the attachment of the tendon of the M. biceps brachii is present on this tubercle. The coracoid process is vestigial. The preserved portion of the scapular spine is rather uninformative, illustrating that, at least proximally, the supraspinous fossa was anteroposteriorly more extended than the infraspinous fossa. The surface of the infraspinous fossa is concave and its outer rim is relatively raised, while the surface of the supraspinous fossa is flat or slightly concave. Both the lateral and the medial surfaces of the scapula display a pair of nutrient foramina placed more or less adjacent to the spine. The medial face is mostly occupied by the subscapularis fossa, which is slightly depressed. Just ventral to the glenoid fossa, there is a deep and elongate groove for the insertion of the tendon of the long head of M. triceps brachii.
Most of the left humerus is preserved ( Fig. 5A–C); a portion of the head and the greater tuberosity are broken off. The right humerus is only represented by its distal quarter. We also provisionally assign to the species a distal fragment of humerus TM 31-99-001 ( Fig. 5D, E); it is not perfectly preserved, especially the lateral epicondyle, but this individual is undoubtedly smaller than the holotype (see Table 5) and has a supracondylar crest that is not as laterally extended distally as in TM 171-01-033. In comparison with most of the extant otters, the humeral epiphysis of the type of S. beyi is overall relatively straight, though it is slightly curved laterally and, in its proximal half, backwards. Thus, the marked anteroposterior curvature observed on most extant species is indistinct in the fossil otter. The diaphysis is transversely compressed and marked by strong ridges. The deltoid crest is distinct and fused with the pectoral ridge in the proximal half of the humerus, about 80 mm from the head (i.e. approximately 45% of the total length of the bone); the area for the attachment of the M. deltoideus is slightly depressed and rugose. It elongates and widens proximolaterad. The pectoral ridge is much stronger than the deltoid crest and present almost throughout the length of the diaphysis. The lateral epicondylar crest is proximodistally very developed and laterally very expanded; its outer rim makes a gentle curve. The anterior face of the crest is concave (insertion area for the M. brachialis and the extensors of the wrist and the digits) and the posterior one convex (insertion area for the M. anconeus). Another welldelimited muscular scar is the attachment area for the Mm. teres major and latissimus dorsi, which forms a proximodistally elongated, 25-mm-long groove on the medial face of the diaphysis; the distal extremity of this attachment is at the level of the distal extremity of the deltopectoral crest. The humeral head is only partially preserved, which pre- ·
vents us from giving a precise description. Only the base of the lesser tuberosity is preserved; it was certainly large and is separated from the greater tuberosity (not preserved) by a wide intertubercular (or bicipital) groove in which glides the tendon of the M. biceps brachialis. The articulation of the distal epiphysis is wide. The capitulum is transversely very extended on the anterior face; it is relatively flat and displays a shallow groove on which the coronoid process of the radius slides. The trochlea is narrow and relatively deep, with a steepened medial lip. The olecranon fossa is deep, distally wide and has a triangular shape. Distomedially to the fossa and to the trochlea, there is a very deep fossa extending distally in a rugose trough for the attachment of the olecranon ligament. The entepicondylar foramen is large and slightly proximodistally elongated; a heavy bar limits it. The radial fossa is deep and wide. The lateral epicondyle is much less laterally extended than the medial one, but it is anteroposteriorly developed and prominent due to the distal extension of the epicondylar crest. The attachment of the M. anconeus on the posterior surface of this crest is extended distally, well beyond the distal margin of the olecranon fossa. The lateral surface of the lateral epicondyle is the area of origin for the tendons of the extensors and supinators of the elbow, and of the carpus and digits; the distinction between them is not clear on the specimen, specifically because the margin of the distal part of supracondylar crest and of the lateral epicondyle is damaged. The medial epicondyle is well developed and triangular though it does not extend as much as in, for example, Pteronura brasiliensis , whose epicondyle has a square outline: here, it is laterally and slightly posteriorly orientated. Except for its posterodistal part, the medial epicondyle is well preserved in the material. The M. triceps brachii medialis inserts on the proximal half of the posterior side, which is slightly depressed and has a ridged medial rim. In extant carnivorans, the anterior face and medial rim of the epicondyle are more complex and support closely placed insertions for flexors and pronators of the forearm. The exact location of the insertion or origin of each of these muscles has been described and/or illustrated in many carnivorans, including mustelids (e.g. Fischer, 1942; Howard, 1973; Leach, 1977). There are obvious problems of homology looking at the muscle name used in the literature, which complicates myological identification and comparisons. The M. palmaris longus, which apparently displays a great variation in location and presence/absence, is an appropriate example. It is said to be absent in the domestic cat and dog in some publications ( Evans, 1993; Barone, 2000; Sebastiani & Fishbeck, 2005), but there is some confusion about the homology of this muscle between humans and other animals [i.e. here the carnivorans ( Spoor & Badoux, 1986)]; Evans (1993: 340) also mentions this homology. The homologous muscle to the M. palmaris longus of humans is the M. flexor digitorum superficialis in Carnivora . Actually, most of the myological descriptions of carnivorans that we use mention the presence of this muscle either as the M. palmaris longus (e.g. Hall, 1926, 1927; Fischer, 1942; Davis, 1964; Howard, 1973) or as the M. flexor digitorum superficialis (e.g. Leach, 1977; Evans, 1993; Barone, 2000), which reinforces the idea that these two names deal with the same muscle. Here, we base our identification primarily on the myology of the extant otters Enhydra lutris and, especially, Lontra canadensis , for which myological descriptions are available ( Fischer, 1942; Howard, 1973). With the homology being clearly established, the precise location of every insertion is not easy in our fossil material, because sandblasting of the bones partly deletes the outline of insertions. We propose the following tentative topography. As in all carnivorans, the small area present on the proximal part of the medial rim of the medial epicondyle is for the origin of the tendon of the M. pronator teres. Immediately distally, there is a rounded and similarly sized insertion area, presumably for the tendon of M. flexor digitorum superficialis. Laterally, a shallow crest separates the latter from a clearly distinct insertion area, to which we assign the tendon of the M. flexor carpi radialis; it is 6.5 mm wide and 4.5 mm high. Finally, the incompletely preserved area posterior and distal to the latter may be the insertion area for one of the tendons of the M. flexor digitorum profundus and/or that of the M. flexor carpi ulnaris. The distalmost part of the epicondyle is not preserved.
The right ulna lacks only the anterior portion of the extremity of the olecranon ( Fig. 5K–N). The left ulna
Lower dentition cL W p4L m1W L W Wtal L/Wmax LtrigoM LtrigoM/L Hmeta Hmeta/L
Hproto
Hproto/L
TM 172-05-001 22.8 13.4 1.70 14.2 0.62 8.0 TM 355-02-002 12.2 20.0 11.6 1.72 7.3 TM 171-01-033* 12.4 9.5 20.3
TM 247-01 - 005 21.5 12.7 1.69 14.0 0.65 7.5 S. sp.
no number 1 22.0 13.0 14.0 1.57
KNM-KP 10034* 2 21.2 13.5 1.57 11.5 0.54
BAR 720′03 11.3 8.4 12.8 13.4 6.5 BAR 416′00
BAR 567′05 3 20.1 13.0 1.55
KNM LU 337 & 338* 4 17.6 10.5 1.68
KNM LU 614 4 9.6 7.7
BAR 1984 ′05 4 17.5 10.6 1.65
SAM PQ L 5000* 12.3 9.5 21.3 13.1 12.8 1.63 14.2 0.67 7.0 SAM PQ L 9138 10
S. kamuhangirei no number* 4 26.0 15.9 1.64
NK, 1988′89 4 14.4
GSI D 33* 5 9.1 6.5 17.5 9.2 1.90
BMNH M 16929 10.0 15.6 9.3 1.68 10.3 0.66 6.7 BMNH M 13175 15.6 9.0 1.73
BMNH M 15397 View Materials 18.5 11.0 1.68 11.9 0.64 6.4
0.35 0.37
0.35
0.33
0.43
0.35 9.3
7.6
7.9
7.0
7.4 0.43
0.37
0.45
0.40
BSP 1930 XI 1 * 12.0 9.1 22.2 14.0 0.63 7.2 Djourabus dabba
TM 293-01-006 & 053* 13.4 10.0 20.9 14.7 14.1 1.42 14.6 0.70 Enhydriodon cf. falconeri
BMNH-M 12350 21.6 12.5 1.73 14.5 0.67 Enhydritherium terra .
UF 100000 6 15.9 9.3 10.4 1.53
UF 18928* 7 17.1 11.2 1.53
UF 32001 7 15.8 10.3 1.53
UF 68001 7 12.0 6.4 16.1 7.5 2.15
MNHN CG 1884-10 5.1 3.8 6.5 4.6 13.4 8.0 8.2 8.7
MNHN CG 1897-982 19.9 11.0 1.81 12.15 0.61 7.15
MNHN A 1914 8.7 6.5 8.5 6 17.8 10.7 1.66 11.4 0.64
MNHN A 1899 9.2 7 9 6.6 18.7 11.4 1.64 12.0 0.64
MNHN A 3388 8.7 7 9.3 6.6 18.5 11.8 1.57 11.6 0.63 6.3 Aonyx congicus
MNHN CG 1947-31 9.6 6.85 7.55 4.7 14.0 7.8 1.79 9.0 0.64
MNHN CG 1973-65 9 6.6 7.8 4.7 14.7 8.05 1.83 8.8 0.60
MNHN CG 1966-216 8.9 6.55 7.4 4.4 13.5 7.15 1.89 8.6 0.64 4.3
MNHN CG 2005-612 14.7 8.4 1.75 8.8 0.60
Lutro. perspicillata
MNHN CG 1962-1646 7.8 6.4 7.8 6 16.5 10.3 1.60 10.6 0.64 5.7
0.32
0.36
0.34
0.32
0.35
7
8.5
4.7
9.7
10.8
0.35
* Holotype; S., Sivaonyx ; terra ., terraenovae ; Lutro., Lutrogale .
Personal measurements, except: 1 from Stromer (1920); 2 from Werdelin (2003); 3 from Morales & Pickford (2005); 4 from Morales et al. (2005); 5 from Lydekker (1884); 6 from Lambert (1997); 7 from Berta & Morgan (1985).
Data are personal except for S. ekecaman , from Werdelin (2003).
consists of its proximal third only, and the olecranon is no better preserved than in the right ulna. The ulna is a robust bone. Except for the extremity of the olecranon, which turns mediad, the bone shaft is rather straight. The olecranon is relatively long and thick, with a squared distal outline, and displays relatively well-marked muscular attachments and insertions ( Fig. 3K–N). Its anterodistal part is unfortunately not preserved. On the posterior part of the distal face somewhat medially, the insertion area for the tendon of the long head of the M. triceps brachii is rounded, deeply marked and extends somewhat distally on the lateral face; it is located anteroproximally to the insertion of the lateral head of the triceps, which lies on the posterolateral side of the olecranon. The latter is about 30 mm long and proximodistally extended, with its distal extremity tapering off. Proximally, the crest-like, lateral rim of this insertion limits the insertion of the tendon for the M. anconeus. A low ridge separates the triceps lateralis insertion from that of the M. flexor digitorum profundus. The insertion of the medial branch of the triceps is not clearly visible, due to the poor preservation of the medial rim of the olecranon. Just distal to the triceps insertions on the medial face, there is a depressed and extended insertion for the tendon of the ulnar head of the M. flexor carpi ulnaris. Just opposite to it on the lateral face of the olecranon, the insertion for the M. anconeus is shallow in comparison; its distal rim is, however, distinct as a low ridge that is nearly perpendicular relative to the long axis of the ulna. This low ridge separates the anconeus insertion from that for the M. abductor pollicis longus. On the left ulna, the latter area is distinctly depressed from the level of the semilunar notch to that of the interosseus tubercle, while the area of insertion for the M. extensor digiti I and II (formerly M. extensor pollicis longus et indicis proprius; Evans, 1993), which lies just posterior to it, is convex, with a distal rim at the level of the middle of the semilunar notch. On the medial face of the olecranon, the insertion for the M. flexor digitorum profundus is well delimited. Proximally, it has an adjacent, oblique boundary with the insertion for the medial head of the triceps, then runs distad between the ulna crest-like posterior rim and the insertion for the tendon of M. brachialis (and, probably, that of one muscle of the pectoral group; see discussion below). Distally, a prominent crest marks its anterior limit (with the insertion of the M. pronator quadratus). The semilunar notch is well rounded. In anterior view, it presents a transverse constriction in its middle part. The anconeal process is wide and laterally particularly prominent; the medial articular surface is more inclined proximad than the lateral surface. The lateral coronoid process is very reduced and located strictly laterally, while the medial coronoid process is prominent and anteriorly projected. The
C
18
17.3 16.3 19.2
17
C
19.1 17.5 19.8 22.5 27.2
C
16
22 18.8 20.7 29.5 31.2
15
C
24.6 19.4 21.8 33 34.9
C
14
26.5 21 23.2 36.8 37.9
13
C
28.1 21.5 24 40.4 43.3
12
C
36.5 29.7 22.1 24.3 43.2 46.8
carnivorans 11 C 37.1 30.8 22.4 24.8 44.7 49.4 non-lutrine C 10 9 C 37.4 31.4 30.5 22.6 22.5 24.9 25 44.2 43.2 51.9 50.8
some and
8
C 30 22 24 26.7 43.7 52.1
Lutrinae C
7 34.7 30.5 20.9 22.9 24.7 41.7 50
in C 6 29.5 19.5 21.2 22.6 38.7 44.8 4. body C 5 31.6 28.5 17.9 19.5 20.5 34.5 39.4 Figure vertebra of caudal
4 C 29.7
27 17 18 30.6 34.4 profile of C 3 25 15.6 16.6 26.8 30.8 vertebral length
2 C 29
24.2 13.9 15.7 23.1 28.6 the the for of 1 C 23.5 13.1 15.1 16.5 21 27 serve
Comparisons. nov. - 033 01 - Table.
4
. sp beyi S 171 TM brasiliensis . P A 1918. felina Lo 1995 - CG 185. Lu lutra - 1996 CG 2466 Ao capensis . - CG 1883 1561 Canis lupus 2005 - CG 79 leo Panthera 2 1954 CG - measurements The radial notch is weakly concave; it faces almost exactly laterally. Just distal to the trochlear notch on the anterior part of the medial face, the area of insertion for the tendon of the M. brachialis is large and depressed, about 30 mm long proximodistally and as wide as 7 mm; it is limited posteriorly by a marked, thick ridge. It is clear that there are two distinct insertion areas. The most anterior and distal insertion area is for the tendon of the M. brachialis. This is also much more proximodistally extended than the second insertion area, which is located on the neck of the coronoid process and is more or less rounded in outline. According to Howard (1973), the tendons of the Mm. pectoantebrachialis and deltoideus (the latter is called M. clavobrachialis by Howard) are attached in this second area in Enhydra lutris while the insertions of these muscles are both placed on the anterior face of the humerus in Lontra canadensis ( Fischer, 1942) . In fact, the M. pectoantebrachialis is not mentioned in most of the anatomical sources we used and therefore it is not clear with what muscle of the pectoralis group the pectoantebrachialis is homologous. According to Howard (1973: 432), this muscle is ‘the most superficial of the pectoral muscle group’ and arises from the sternum, starting from the manubrium anteriorly and extending posteriorly to the level of the second rib. This muscle probably corresponds to the M. pectoralis transversus of other authors (e.g. Barone, 2000). Whatever the name of this muscle, in other mustelids ( Spilogale , Mephitis , Martes , Taxidea ; Hall, 1926, 1927; Leach, 1977), ursids ( Davis, 1964), various additional wild ( Potos , Paradoxurus , Caracal ; Beswick- Perrin, 1871) and domestic carnivorans ( Felis and Canis ; Evans, 1993; Barone, 2000), neither the pectoral muscles nor the deltoid attach on the ulna. The M. pectoantebrachialis is, however, described in the domestic cat ( Wischnitzer, 1993; Sebastiani & Fishbeck, 2005), where it attaches on the antebrachium fascia. The identity of the attachment adjacent to that of the M. brachialis in TM-171-01-033 is therefore unclear. Regardless, the size and depth of the entire area supports the attachment of the strong flexors of the elbow. The interosseus tubercle is very prominent and located at mid-shaft. In its distal third, the diaphysis displays marked crests that clearly delimit a flat, 10-mm-wide insertion area for the M. pronator quadratus; the crest between this insertion and that for the M. flexor digitorum profundus is particularly prominent, but distally does not reach the level of the articulation for the radius. The styloid process is large, and the articulation for the scapholunar is slightly larger than that for the radius. Both articulations are prominent and separated by a deep and wide notch.
The left radius is nearly complete ( Fig. 5H–J), displaying small cracks and lacking some fragments of the two epiphyses, including the part distal to the
terra . P. brasiliensis Lu. lutra
TM 171-01-033 TM 31-99-001 M. A. R. A 1918 CG 1996-2466 Lo. felina CG 1995 -185 Lutro. persp. CG 1960-3670
Condylobasal L of skull
Lm1 20.5 Caudal vertebrae
C2 DBL 29
C2 TH 33 Scapula articulation: APD 35 articulation: MLD 24.3 neck: min APD 30.7 Humerus
FctL 178
L (trochlea-dist margin of V-deltoid) 103.6
L prox (boundary epicondylar crest-trochlea) 81.5 prox epi: APD 49
dist epi: max MLD 53.3 dist epi: max APD 24.5 dist epi: max MLW art. on ant. face 36.7 min APD trochlea 14.8 min MLD dia 16 APD same level 23 APD at mid-FctL 16.5 MLD at mid-FctL 24
Fct L/ML max D of dist epi 3.34 IS 1.10
L (head-t.m and l.d. insertion) 80.50 Ulna max L 185 Olecranon L 43.7 Shaft L 149.3
L (dist epi-dist rim osseus tubercle) 80 Olecranon proportion 0.29
151.5 122 15.9 18.4 13.75
24.2 15.7 24.3 15.1
24.8 18.5 16.3 11.3 22 16
109 98.8 87.8
39 46.5
38.6 35.5
30.6 23 46.5 42 36.4 30.5 23.3 17.5 12.8 31.3 22.5 19.5 14 11 8
9 8.1
14.2 14.5
14.2 14.5
9.2 8.1
2.71 2.88
0.97 0.84
51.00 40.50
116 99.5 86 33 20.2 76.8 67.5 25 30 0.43 0.30 107.2 15.5
13.9 16.2
17.8 10.9 14.3
80 45 28 21.3 27.8 13 16.5
7.6
7.1 12.2
7.2 12.2
2.88
0.94 37.00
80.1 21.5 59.9 28.5
0.36
18.5 11.3 16.1
84.2 46.5 30.2 22.3 26.3 13.1 15.3
8.2
7.1
9.5
7.3
9.8
3.20
1.34 37.50
83.6 19.4 65.8 31.5
0.29
Radius max L (= FctL) 146 prox epi: MLD 22 prox epi: APD 16.1 dist epi: MLD 33.6* dist epi: APD 19*
L (dist epi-dist rim radial tuberosity) 114 Scapholunar body: MLW 18.5 body: APW 17.5 max MLW (incl. post. tubercle) 23.6 max APW (incl. post. tubercle) 22 Metacarpals
Mc I max L 37.50 Mc II max L 48.80 Mc III max L 55.8 Mc IV max L
Mc V max L
Ratio Mc III to limb L 0.147 Ratio of Mc III to Mc I 1.49 Ratio of Mc III to Mc II 1.14 Ratio of Mc III to Mc IV
Ratio of Mc III to Mc V
Ratio of Mc II to Mc I 1.30 Ratio of Mc II to Mc IV
Ratio of Mc II to Mc V
Ratio of Mc IV to Mc I
Ratio of Mc IV to Mc V
Ratio of Mc V to Mc I
Ratio of Mc II to limb L 0.13 Ratio of Mc I to limb L 0.10 Brachial Index 0.82 FctL radius/Lm1 7.12 FctL humerus/Lm1 8.68 FctL radius/C2 DBL 5.03 FctL humerus/C2 DBL 6.14
87 74.2 64.2 15 12.2 10.2 8.6 22.1 14.8 14 10.8 54.2 48.5
15.5 10.6 13 8.3 16.5 12.2 15 11
24.80 16.80 35.00 22.20 40.1 28.6 42 29.9 34.50 22.70 0.188 0.158 1.62 1.70 1.15 1.29 0.95 0.96 1.16 1.26 1.41 1.32 0.83 0.74 1.01 0.98 1.69 1.78 1.22 1.32 1.39 1.35 0.17 0.13 0.13 0.10 0.80 0.75 0.73 5.47 4.03 4.67 6.86 5.37 6.39 3.07 4.09 4.08 5.59
56 11.5
7.5 13.4
9 43.1
10
8 10.5 9.5
15.50
20.70
25.1
26.4
20.60 0.156 1.62 1.21 0.95 1.22 1.34 0.78 1.00 1.70 1.28 1.33 0.13 0.10 0.70 3.61 5.16 4.03 5.76 62.6 12
13.6 10.1 50.4
0.74
*Estimated value.
Data are personal, except those for Enhydritherium terraenovae , from Lambert (1997). Abbreviations: Enhydrit. terra ., Enhydritherium terranovae ; M.A.R., Moss Acres Racetrack; persp., perspicillata .
S. beyi sp. nov. cf. Aonyx sp. S. hendeyi E. terra . P. bras . Lu. lutra Lo. felina Lutro. persp. Ao. capensis
| TM |
Teylers Museum, Paleontologische |
| MNHN |
Museum National d'Histoire Naturelle |
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