Devinophoca emryi

Rahmat, S. J. & Koretsky, I., 2016, First Record Of Postcranial Bones In Devinophoca Emryi (Carnivora, Phocidae, Devinophocinae), Vestnik Zoologii 50 (1), pp. 71-84 : 73-80

Devinophoca emryi ( fig. 1–6 ; tables 1–6)

P a r a t y p e. Left humerus, SNMZ 25507.

Type locality. From the locality of Stokerau lime plant, Bonanza Hill , Devínska Kobyla, outskirt of Bratislava, Slovak Republic .

Range. Badenian (= Langhian), early Middle Miocene (16.26–14.89 Ma); Central Paratethys, Vienna Basin of Western Slovakia.

Emended diagnosis. Diagnosis for skull (holotype), mandibles and teeth was published by Koretsky and Rahmat (2015). Humeral head rounded, flattened, compressed craniocaudally (similar to Monachinae ); ratio of head’s width to height is 0.94 (similar to Monachinae ); intertubercular groove deep, short, narrow (similar to Monachinae , in contrast to Cystophorinae and Phocinae ); greater tubercle oval, well developed, slightly elevated above head; lesser tubercle oval, flattened, almost same level as head (in contrast to Monachinae ); proximal part of deltoid crest located slightly higher than head and lesser tubercle; deltoid crest strongly developed, short, terminates near middle of diaphysis; greatest width of deltoid crest located in middle (similar to Cystophorinae, in contrast to Phocinae ); deltoid tuberosity small, located in middle of deltoid crest (similar to Cystophorinae); medial epicondyle flattened, extends to middle of coronoid fossa (in

Characters Devinophoca emryi Absolute length 128.5; 130.1 Length of deltoid crest 80.5; 82.4 Height of head 27.1; 28.1 Height of trochlea 19.2; 23.8 Width of head 28.3; 29.8 Width of deltoid crest 10.8; 11.6 Width of distal epiphysis 38.4; 40.1 Width of proximal epiphysis 40.3; 40.8 Width of trochlea below 27.5; 27.9 Width of trochlea, frontal view 19.7; 20.4 Transverse width of diaphysis 15.2; 16.4 Thickness of proximal epiphysis 59.4; 60.6 Thickness of medial condyle 26.7; 26.8 Thickness of lateral condyle 21.5; 23.2 Diameter of diaphysis with deltoid crest 35.6; 35.9

contrast to Cystophorinae); coronoid fossa oval, shallow (similar to Cystophorinae); entepicondylar foramen large, oval, with wide bridge over it; middle of humeral trochlear crest located at level of coronoid fossa (similar to Phocinae ).

Ulna’s olecranon large, curves caudally; olecranon tuberosity prominent; trochlear notch flattened, well developed; radial notch very pronounced, concave in shape; coronoid process round, flat, shallow; anconeal process very large, wide, protrudes; styloid process well developed, oval; distal part of ulna flattened; upper part of trochlear notch wider than lower.

Innominate’s ilium thin, excavated on ventral surface (similar to Lobodontini, in contrast to Cystophorinae, Monachinae and especially Phocinae ); iliac tuberosity flattened, small, averted; iliac crest thin, well outlined, not averted (similar to Monachinae ); iliac spine thin (similar to Monachinae , in contrast to Cystophorinae and Phocinae ); acetabulum deep, with pronounced rim.

Femoral head small, round, seated on distinct lip on short and wide neck (similar to Phocinae ); greater trochanter extends above head; proximal and distal parts of greater trochanter approximately of equal width (similar to some Phocinae ); trochanteric fossa oval, deep, with overhanging lip of medial part of greater trochanter (in contrast to Phocinae ); supracondylar fossa shallow, wide, elongated; smallest width of diaphysis shifted towards proximal end of bone (similar to Monachinae and Cystophorinae); lateral condyle significantly larger than medial (in contrast to Cystophorinae); ratio between proximal and distal epiphyses 1.04 (in contrast to Cystophorinae, Monachinae and Phocinae ).

R e f e r r e d s p e c i m e n s. In addition to the holotype (skull), the following specimens were found: scapula: SNMZ 14537 (R., proximal end); humerus: SNMZ 25507 (L.); radius: SNMZ 25505 (proximal end); ulna: SNMZ 25504 (L.); innominate: SNMZ 14543 (L.); femur: SNMZ 14544 (R.); tibia and fibula: SNMZ 14545 (L., proximal half) .

D e s c r i p t i o n. Scapula ( fig. 1 ). The incomplete scapula has a well-developed glenoid fossa that is concavely shaped and has a thin mushroom-like lip. The transverse diameter of the glenoid fossa is 31.5 mm, the anteroposterior diameter of the glenoid fossa is 20.5 mm and the width of the neck is 29.4 mm. The coracoid process, acromion process, spine and other features cannot be described as they are missing.

Humerus ( fig. 2 , A–D; table 1). The complete bone is well preserved. The head is well developed, flattened and compressed craniocaudally. The ratio between the length and width of the head is 0.94. The lesser tubercle is well developed, oval, and located almost at the same level as the head. In contrast to Pontophoca sarmatica (Monachinae) , the lesser tubercle does not parallel the bone’s axis, but deviates slightly posteriorly from the bone’s axis as in Cryptophoca maeotica (Phocinae) . The greater tubercle is located above the head, is well developed and flattened on its lateral side as a well-outlined large oval facet, a unique character for the Subfamily Devinophocinae . The width of the anatomical neck between the head and lesser tubercle is significantly broader than the width between the head and greater tubercle (also a unique character for Devinophocinae ). The intertubercular groove is deep and narrow. The deltoid crest is strongly developed with the widest portion of the deltoid crest located in its middle, similar to Pachyphoca ukrainica (Cystophorinae) . The crest extends a little more than half the length of the bone and ends almost as an invisible ridge, reaching the proximal edge of the entepicondylar foramen, but does not reach the coronoid fossa, as in the monachine Callophoca obscura ( fig. 2 , E). The deltoid tuberosity is small, markedly convex (as in Pontophoca sarmatica ) and is located in middle of deltoid crest. The musculospiral groove is absent. The lateral epicondyle is narrow, reaching the distal part of the deltoid crest (as in Callophoca obscura ) and extends more than twice proximally than the medial. The medial epicondyle is flattened, is located lower than the lateral, and spreads from the middle part of the entepicondylar foramen, extending to the middle of the coronoid fossa. The entepicondylar foramen is large and oval, with a wide bridge over it, like in the phocine Leptophoca lenis ( fig. 2 , F) and the cystophorine Pachyphoca chapskii ( fig. 2 , G). The coronoid fossa is shallow, oval in shape, and ends at the same level as the tip of the entepicondylar foramen. The middle of the humeral crest of the trochlea ( fig. 2 , E–G) is at the level of the coronoid fossa (similar to Phocinae ), unlike Monachinae (arch-like, elevated over the coronoid fossa) and Cystophorinae (rising wave-like over the coronoid fossa). The olecranon fossa is shallow, narrow and oval shaped.

Radius ( fig. 3 , A–C). The incomplete radius is missing its distal end. The radius has a well developed, oval-shaped head and a narrow, elongated neck. The fovea of the head is welloutlined, smooth and concave in shape. The circumferential articularis on the lateral aspect of the bone is well-outlined, ridged and does not reach the level of the radial tuberosity, unlike in Callophoca obscura (Monachinae) and similar to Leptophoca lenis (Phocinae) .

Ulna ( fig. 3 , D–E; table 2). The complete bone is long, slender, almost the same length as Pachyphoca chapskii (Cystophorinae) and has a significantly large olecranon, in contrast to Praepusa vindobonensis (Phocinae) and P. chapskii , where the olecranon is short. The medial surface is flat and the most proximal portion of the bone just below the olecranon is concave, unlike in Pachyphoca ukrainica and P. chapskii (Cystophorinae) , where none of the medial surface has any concavity. The well-developed olecranon is unusually long, thin, fan-shaped and curves caudally, with a prominent olecranon tuberosity. The narrow fossa at the level of the trochlear notch for insertion of the flexor digitorum profundus (= communis) muscle contrasts with the protuberance present at the same position in P. chapskii . The presence of this elevated ridge implies that P. chapskii seals have a more developed flexor digitorum profundus muscle (for flexing the forelimb; Piérard, 1971) than this species of Devinophocinae . Morphology of this character suggests that the condition in P. chapskii is more primitive than the geologically older-aged fossil ulna of Devinophocinae , where this character is more advanced. The broad, short and very bulky rugosity for the brachialis muscle insertion has a well-developed ridge (unlike in P. chapskii ), but its location below the trochlear notch is similar to P. chapskii . On the lateral surface, a shallow, wide and prominent fossa (in contrast to P. chapskii ) is present for the abductor pollicis muscle. This fossa is absent in Pr. vindobonensis . Along the middle of the diaphysis, a long, shallow groove extends from the caudal edge of the articular surface, as a continuation from the abductor pollicis muscle fossa, to the well-developed ulnar protuberance (similar to P. chapskii , but in contrast to P. ukrainica ). The ulnar protuberance is significantly thicker and wider in P. chapskii . The trochlear notch is flattened and well developed. The radial notch is also

Characters Devinophoca emryi Width of incisura trochlearis in upper part 17.2

Width of incisura trochlearis in lower part 15.9 Maximal width of middle part of diaphysis 19.9 Maximal width of distal epiphysis 22.4

very pronounced (unlike in Pr. vindobonensis and P. chapskii ) and concave in shape. The radial notch in Callophoca obscura and Pliophoca etrusca (Monachinae) is absent, replaced by a sharpened ridge. The coronoid process is rounded, flat and very shallow. In contrast to P. chapskii and Pr. vindobonensis , the coronoid process does not protrude over the radial notch. The anconeal process is very large, wide and protruding, similar to P. chapskii and Cal. obscura . The head and styloid process are preserved, with the prominent styloid process having an oval shape. The distal part of the ulna of Devinophocinae remains flattened up to the styloid process, in contrast to P. chapskii where it becomes enlarged and thicker than the diaphysis.

Innominate ( fig. 4 ; table 3). As in other Monachinae and Cystophorinae, the ilium is fairly thick. The iliopectineal eminence is small and is situated higher than the proximal

Characters Devinophoca emryi Length from center of acetabulum to iliac crest = A 71.9

Width of acetabulum 27.2 Height of acetabulum 26.9

Width of level of iliac crest = O 55.3

Ratio

O/A 76.9

border of the acetabulum. The greater sciatic notch is almost straight, with a slight concavity (similar to P. ukrainica ). A shallow depression for the gluteus medius muscle is located on the medial aspect of the ilial wing. There is a shallow auricular fossa on the lateral aspect of the ilium for origin of the psoas major muscle. The alar spine does not protrude far. The edges of the acetabulum are raised high above the plane of the bone (similar to P. chapskii ). The acetabulum is conical in shape, a primitive character (similar to P. chapskii ). Above the acetabulum is a deep and narrow depression for insertion of the rectus femoris muscle. The ischium and pubis are not preserved.

Femur ( fig. 5 , A–B; table 4). The femoral head is small in size, round and seated on a distinct lip. The neck is short and wide. The greater trochanter extends proximally above the head, with its proximal part somewhat wider than the distal, similar to the cystophorine P. ukrainica ( fig. 5 , E). The greater trochanter is obliquely oriented along the bone’s axis, but not as extreme as in P. chapskii . The trochanteric fossa is deep, oval in shape and opens proximally, reaching the distal half of the greater trochanter. The lesser trochanter is not

Tibia and fibula ( fig. 6 , A–C; table 5). The two condyles are concave in their centers, with the lateral condyle more concave than the medial. Both medial and lateral condyles are oval in shape. The intercondyloid eminence is well pronounced and only slightly raised above the two pronounced borders of the condyles. On the ventral side of the bone, the tibial tuberosity is flattened, triangular in shape and well developed. The distal portions of the tibia and fibula were destroyed.

Figures

Fig. 1. D. emryi scapula, SNMZ 14537 (R., incomplete) in: A — anterior; B — posterior; C — lateral views.

Fig. 2. D. emryi humerus, SNMZ 25507 (L., paratype) in: A — medial; B — lateral; C — caudal; D — cranial views. Cranial views of: E — left humerus of Callophoca obscura (IRSNB 301, male); F — left humerus of Leptophoca lenis (USNM 412115); G — left humerus of Pachyphoca chapskii (NMNHU-P 64-523). The tip of the arrows indicate the shape of the middle of the humeral trochlear crest in: E — Monachinae (arch-like, elevated over the coronoid fossa); F — Phocinae (at the level of the coronoid fossa (similar to D. emryi); G — Cystophorinae (rising wave-like over the coronoid fossa).

Fig. 3. D. emryi radius, SNMZ 25505 (incomplete) in: A — dorsal; B — ventral; C — cranial views and ulna SNMZ 25504 (L.) in: D — medial; E — lateral views.

Fig. 4. D. emryi innominate, SNMZ 14543 (L., incomplete) in: A — lateral; B — medial; C — posterior views.

Fig. 5. D. emryi femur, SNMZ 14544 (R.) in: A — caudal; B — cranial views. Caudal views of: E —left femur of Callophoca obscura (USNM 437715, male); F — right femur of Leptophoca amphiatlantica (reversed, USNM 263648); G — right femur of Pachyphoca ukrainica (reversed, NMNHU-P 64-166).

Fig. 6. D. emryi tibia and fibula, SNMZ 14545 (L., incomplete) in: A — caudal; B — cranial; С — proximal views. Right calcaneus and astragalus in: D — dorsal; E — plantar views.