Eucyon khoikhoi, Valenciano & Morales & Govender, 2022
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publication ID |
https://doi.org/ 10.1093/zoolinnean/zlab022 |
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publication LSID |
lsid:zoobank.org:pub:FFBE273B-E85D-44B9-951A-B7EE05E00E6C |
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DOI |
https://doi.org/10.5281/zenodo.6360697 |
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persistent identifier |
https://treatment.plazi.org/id/039187B3-6938-5A09-FEE5-FCF60060FAD3 |
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treatment provided by |
Plazi |
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scientific name |
Eucyon khoikhoi |
| status |
sp. nov. |
EUCYON KHOIKHOI SP. NOV.
( FIGS 1–8 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 View Figure 8 )
1974 Canidae View in CoL incerta sedis Hendey: 67.
1981a gen. and sp. not det.? aff. ‘ Canis ’ brevirostris Hendey View in CoL : 50.
1981a Vulpes sp. Hendey: 50.
1993? Eucyon sp. Rook: 45.
2008 cf. Eucyon García : 589.
2009 Eucyon sp. Rook: 741.
2009 Eucyon sp. Montoya, Morales & Abella: 719.
2010 Eucyon sp. Werdelin & Peigné: 609, fig. 33.2A.
2016 Eucyon sp. Hartstone-Rose et al: 2, fig. 1A.
Zoobank registration: urn:lsid:zoobank.org:act:EFC6184C-759D-4AEC-B0DB-CEA578D79898
Diagnosis: Eucyon of similar size to that of the type species of the genus E. davisi of North America. Upper premolars (P2–P3) relatively short and robust, separated by a small diastema. P4 robust, with strong protocone. Robust and large M2, with respect to M1. Short and tall lower premolars. p3 with small distal accessory cuspid. Robust p4 with stronger and more extended distal accessory cuspid, and presence of a second distal accessory cuspid, comprising a small talonid. Robust m1, with high protoconid, talonid without transverse cristid between the entoconid and the hypoconid. m2 relatively long compared with m1, with a complete trigonid and a narrow talonid.
Differential diagnosis: Differs from E. davisi from North America ( Tedford et al., 2009) in a more robust lower dentition (p4–m1 and m2), with a longer m 2 in relation to the m1. In relation to the former character, the M2 long and more robust. The P4 is also more robust. The m1 has a better developed hypoconulid shelfhypoconulid shelf, comprising a markedly higher m1 protoconid. Most of these differences between E. khoikhoi and E. davisi are observed in the individuals of E. davisi from different localities in China ( Tedford & Qiu, 1996). The Chinese sample has more robust premolars, especially P4 and p4, and more robust second molars (M2 and m2) than those of the North America populations. Therefore, they are more like E. khoikhoi . The Chinese E. davisi maintain small M2 and m2 lengths in relation to the first molars, which clearly distinguish them from E. khoikhoi . The difference in the length of the second molars with respect to the length of the m1 also allows the new Langebaanweg species to be distinguish from other Eucyon spp. , which preserve comparable molar dentition: Eucyon debonisi , E. odessanus , E. wokari García, 2008 and E. zhoui . It differs from E. debonisi by the greater gracileness of the lower dentition in the Spanish species, particularly in the premolars and the carnassial teeth (P4 and m1). It differs from E. wokari in the anomaly of the alveolus in the maxilla for an M3, in the morphology of the m1 talonid, which in the Ethiopian species has transverse cristids that connect the hypoconid to the entoconid ( Garcia, 2008). Eucyon marinae Spassov & Rook, 2006 differs from E. khoikhoi in the advanced morphology of the lower premolars and m1, which, although it lacks the transverse cristid between the hypoconid and the entoconid, the hypoconid is extremely large with respect to the entoconid, a trait that could indicate that this species moved away from the most common morphotypes of the Eucyon species. Eucyon kuta differs from E. khoikhoi in the robustness of the p2–3, unknown in other species of the genus, as the authors of the species point out. Eucyon monticinensis ( Rook, 1992) possesses, despite the limited sample, a notable intraspecific variability, which, like E. debonisi , could be interpreted as sexual dimorphism ( Montoya et al., 2009). The M1 are at the maximum of robustness of the group, different from E. khoikhoi , and correspond with the size and proportions of the m1 of the type ( Rook, 1992). It also differs from E. khoikhoi in the greater gracileness and size of the m2, traits that are common in both Italian and Spanish species. It differs from Eucyon intrepidus in its larger size and more robust M1 and m1. This species has the smallest M1 recorded in the Upper Miocene of Africa, close to the smallest specimens of E. debonisi and E. khoikhoi .
Etymology: Named after the Khoikhoi (KhoeKhoen) people, formally a nomadic pastoralist indigenous population of southern Africa who thrived for over 1000 years in various regions of South Africa including the Western Cape, where this species was discovered. We honour Khoi heritage and ancestry.
Holotype: SAM-PQL-31272 , comprising the skull, two hemi-mandibles, two fragmentary humerii, two radii, including a right complete and a left fragmentary one, and five cervical vertebrae, including the atlas, axis and cervical 3–5.
Paratype: SAM-PQL-72215, right maxillary including M1–M2.
Referred specimens: SAM-PQL-40041, old and pathological individual comprising the fragmentary left hemi-mandible with p1, broken p4 and m1–3, the fragmentary right hemi-mandible with p1–m2, the right proximal epiphysis of the scapula, the right proximal epiphysis of the humerus, the right proximal epiphysis of the ulna, the left distal epiphysis of the radius, the complete right metacarpals II–V (Mc IV, broken), the left both pyramidal and magnum, the right ectocuneiform, eight sesamoids, four first phalanges, three second phalanges, one ungual phalanx and one caudal vertebra (fourth caudal); SAM-PQL-24976B, right I3; SAM-PQL-24976B, left Cx; SAM-PQL-15526B, left P2; SAM-PQL-15184B, left P4; SAM-PQL-72203, right fragment of P4, including the protocone; SAM-PQL-72204, left fragment of P4, including the protocone; SAM-PQL-72205, left fragment of P4, including the protocone; SAM-PQL-72207, left fragmentary P4; SAM-PQL-72208, right M1; SAM-PQL-69621B, left maxillary, including M1–2; SAM-PQL-15588 B/C, right M1; SAM-PQL-50497, left M1; SAM-PQL-15219B, left M1; SAM-PQL-15705A, left M2; SAM-PQL-72217, right M2; SAM-PQL-72206, left M2; SAM-PQL-72218, indeterminate root; SAM-PQL-40308, fragmentary left hemi-mandible with m1–3 alveoli, two fragmented tibiae and eight fragments of vertebrae; SAM-PQL-72228, right cx; SAM-PQL-50112, left cx; SAM-PQL-72221, fragmentary right cx; SAM-PQL-72222, fragmentary right cx; SAM-PQL-69621d, fragmentary right cx; SAM-PQL-72223, left fragmentary hemimandible with m2-3 alveoli; SAM-PQL-50111, right fragmentary hemi-mandible with m2–3 alveoli; SAM-PQL-722219, right fragmentary hemi-mandible with complete p1, p3–4 and a broken p3 at the base crown; SAM-PQL-72220, left fragmentary hemi-mandible with broken p3-p4 and mesial part of m1 at the base of the crown, plus distal root of m1; SAM-PQL-69621A, fragmentary right hemi-mandible with broken p3– m2 at the crown base and with m3 alveolus; SAM-PQL-50110, left fragment of hemi-mandible with c and p1 alveoli and a fragmentary p2; SAM-PQL-50497A, left fragmentary hemi-mandible with both m1 and m3 alveolus and a complete m2; SAM-PQL-15381 A/1, left p2; SAM-PQL-72216, left m1; SAM-PQL-72166, left fragment of the m1 trigonid; SAM-PQL-50113A, distal fragment of a right m1, including protoconid, metaconid and talonid; SAM-PQL-50113B, right m2; SAM-PQL-72225, right m1 talonid; SAM-PQL-72212, left m2; SAM-PQL-72211, fragmentary left m2; SAM-PQL-16120A, right m3; SAM-PQL-72213, right m3; SAM-PQL-72209, right Dp2; SAM-PQL-72210, left dp4; SAM-PQL-72214, fragmentary talonid of a left dp4; SAM-PQL-72226A, left fragment of dp3; SAM-PQL-72226B, left dp4; SAM-PQL-20424, right fragmentary humerus with most of the shaft and the distal epiphysis; SAM-PQL-23331, right radius; SAM-PQL-15323, atlas; SAM-PQL-15174, axis; SAM-PQL-15160, third cervical vertebra.
Type locality: Langebaanweg ‘E’ Quarry, Western Cape, South Africa.
Age: Langebaanweg ‘E’ Quarry spans the Middle Miocene (Langhian, 16–12 Mya) to the Early Pliocene (Zanclean, 5.2 Mya) ( Tankard & Rogers, 1978; Hendey, 1989; Roberts, 2006a,b; Roberts et al., 2011). The bone bed occurs at the base of the MPPM within the channel fill of the LQSM ( Roberts et al., 2011). The specimens of Eucyon khoikhoi are recovered from the MPPM and LQSM which dates to Early Pliocene, 5.2 Mya (see Roberts et al., 2011).
Description
Skull and upper dentition: The type skull SAM-PQL-31272 is well preserved, without deformation ( Fig. 1 View Figure 1 ; Tables 1 View Table 1 , 2 View Table 2 ). Portions of the palatine, and both pterygoid and the basisphenoids, are missing. The cranial sutures and the absence of wear of the dentition, suggests it is a young adult. Dorsally, the overall morphology is reminiscent to C. aureus . It has long nasal bones, with the muzzle similar to that of V. chama , C. aureus and C. latrans and relatively shorter compared to L. mesomelas . A small infraorbital foramen is located above P3. It has a big and round orbital bone. It has a frontal sinus invading the base of the postorbital process, but a minor dorsal depression is present on the process, being less marked to those the one of the African vulpini V. chama and O. megalotis .
The forehead is not as high as in C. lupus , resembling those of the jackals C. aureus and L. mesomelas , the coyote ( C. latrans ) and vulpini. On the right, the sharper and robust frontal process of zygomatic is preserved in the zygomatic arch.
A thick and broad sagittal crest is present in the parietal area. The occipital protuberance extends beyond the occipital area, and connects with the prominent nuchal crests, which are more laterally expanded than those of living jackals and V. chama and O. megalotis . The cranium is lateromedially wide at the temporal level. In ventral view, the palatine fissure is large but broken.
The palatine sulcus is not preserved. The major palatine foramen is situated between P4 and M1, as in C. aureus and V. chama , and in a more caudal position than L. mesomelas . Neither the pterygoid bones nor hamulus processes are preserved, but both left oval and caudal foramina are preserved. The bulla is large and swollen. The right one has the ectotympanic bone missing, the petrosal bone and the bullar septum are partially preserved. The rostroventral area of the right one is broken. A large foramen lacerum and a small musculotubal canal are located in the most rostral area of the bulla. It has a round external acoustic meatus and a round and smaller stylomastoid foramen, similar to that of L. mesomelas and much smaller than the analysed vulpini. In the distal part of the bulla, the tympano-occipital fissure is large and oval. A small hypoglossal canal is located distally to the fissure. The paroccipital process is ventrally projected. It is well developed and extends over the bulla, displaying a strong bone bar. Both mastoid and paroccipital processes are similar to those of C. latrans , C. aureus , L. mesomelas and unlike V. chama and O. megaloti. In caudal view, the nuchal area is triangular, comprising a complete occipital condyle.
The incisors are set in a parabolic row.I3 is larger than I2. There is a diastema between the I3–C and between the P1 and P2. The I3 is tall with a single cusp, lingually curved. There is a small distolingual cingulum ( Fig. 2A, B View Figure 2 ). The C is oval, showing a marginal lateromedial compression. Its crown is high and thin. In distal view it is slightly sigmoidal ( Fig. 2C View Figure 2 ). P1 single rooted. P2 and P3 relatively short, without mesial accessory cusps. P2 with residual accessory cusp associated with the distal crista. P3 with well-developed distal accessory cusp ( Fig. 2 View Figure 2 ) and P4 has no parastyle. It has a carnassial notch. The protocone is low, conical and located in line with the mesial border of the paracone. The fragmentary specimen SAM-PQL-72205 has the protocone more mesially projected. An inflection is present between the protocone and the mesial border of the paracone in all the P4s ( Fig. 2E–H View Figure 2 ). There is a weak lingual and mesial cingulum ( Fig. 2E View Figure 2 ). There is a wide variability in the measures and morphology in the recovered sample of the first upper molar ( Fig. 2 View Figure 2 ). Most of the M1s are worn or broken, except SAM-PQL-31272 and SAM-PQL-50497 ( Fig. 2A, M View Figure 2 ). It is subquadrangular in occlusal view, with a rectilinear mesial wall and the distal one with an inflexion below the metacone. It has a strong parastyle with a welldeveloped buccal cingulum. Paracone and metacone are subequal in height. The paraconule is small, but well preserved in the specimen SAM-PQL-50497 ( Fig. 2M View Figure 2 ). The protocone is tall and mesially located. It has a large metaconule which connects to the metastyle and the buccal cingula by a tall crista. It has a deep trigone valley. There is a well-developed mesial cingulum, connecting the parastyle with the lingual wall of the protocone. It possesses a tall and bevelled hypocone.
The M2s show a wide intraspecific variability with some specimens having broader talons ( Fig. 2J, K View Figure 2 ) and others reduced ones ( Fig. 2P, Q View Figure 2 ). SAM-PQL-72206, has the biggest M2 of E. khoikhoi recovered, with a slightly different morphology and no worn cusps. The M2s have a kidney-shaped occlusal, with a highly developed paracone compared to the metacone, a protocone located in a more central position to those of the M1 and with a strong labial cingulum ( Fig. 2M View Figure 2 ). Mandible and lower dentition: The overall morphology of the mandibles of E. khoikhoi ( Fig. 3 View Figure 3 ; Tables 1 View Table 1 , 3 View Table 3 ) are similar to those of the living jackals of the genera Canis and Lupulella , being easily distinguish from the African vulpini. SAM-PQL-40041 shows a worn dentition and several dental and bone pathologies. The most complete mandible belongs to the type SAM-PQL-31272. It has a relatively tall coronoid process and a deep masseteric fossa. The articular process is in line with the tooth row and the angular is well developed similar to the canini. The mandibular corpus is low. There are two main foramina on the mandibular corpus, below p1 and p3. There are diastemata between c and p1, and p1–p4. The c is short and robust at the base of the crown. It is distally curved and possesses a lingual keel. Premolars are without mesial accessory cuspid, relatively short and with high main cuspid. There are small diastemata between c–p1, p2–p3, and longer between p2–p1. The p1 is uniradiculate and unicuspidated. The p2 is longer than the p1, double rooted and has no accessory cuspids. The distal area has a small keel. The p3 has a small distal accessory cuspid and a high distal cingulum.
The p4 is robust, comprising stronger and more extended distal accessory cuspid. There is a second accessory cuspid behind the previous one, which is double in the left hemi-mandible of the specimen SAM-PQL-31272, but single in SAM-PQL-72220 ( Figs 3 View Figure 3 , 4D View Figure 4 ). There is a high distal cingulum. The m1 is robust with a low paraconid compared to the protoconid, which is relatively high in relation to the length of the molar. There is a strong metaconid extending slightly beyond the distal wall of the protoconid. Its talonid has a strong hypoconid with the highly developed mesial cristid. The entoconid, although smaller in size than the hypoconid, is strong and extends mesially with a small pre-entoconid, and internally develops a small cristid ( Figs 3 View Figure 3 , 4 View Figure 4 ). However, both hypoconid and entoconid are well separated. The talonid valley is divided into two parts, the mesial one is deep and the distal one is shorter, which is closed by a bifurcated hypoconulid in a distocentral position ( Figs 3 View Figure 3 , 4 View Figure 4 ). The m2 is also robust. It is oval, with a complete trigonid and a highly developed buccal cingulum ( Figs 3 View Figure 3 , 4H–J View Figure 4 ).
The paraconid is small and is attached to the protoconid and continues in a high mesial cingulum that connects with the base of the metaconid, which has an additional cuspid in mesial position, enclosing a small trigonid valley. The metaconid is taller and larger than the protoconid. Buccally, the base of the protoconid is clearly expanded. The talonid is narrower than the trigonid. The hypoconid is the most developed cuspid and is mesially continued by the oblique cristid. The entoconid is bifurcated. The m3 is reduced and has one root. It is round with low cuspids. The largest cuspids are the protoconid and metaconid ( Figs 3A1–3 View Figure 3 View Figure 1 View Figure 2 , 4K, L View Figure 4 ).
Deciduous dentition: The deciduous dentition of this new taxon represents the first non-definitive teeth of Eucyon recovered. It is similar to that of the living L. mesomelas , although several differences distinguish both canids ( Fig. 5 View Figure 5 ). It shows a wide range of variability in terms of size and shape, especially in the lower deciduous carnassial (dp4). The DP2 (SAM-PQL-72209, Fig. 5A View Figure 5 ) is a slender and long simple tooth, without accessory cusps. Distally a high cingulum is present.
The dp3 recovered is a fragmentary distal portion of the tooth, comprising a noticeable distal cingulum ( Fig. 5B View Figure 5 ). There is a great variability in size in the dp4s founds ( Fig. 5C–E View Figure 5 ). Among them SAM-PQL-72214 is much smaller and narrower to that of SAM-PQL-72210 and SAM-PQL-72226B. The dp4 has a well-developed metaconid, with a more distal position than in the m1. The talonid is wide and simple. It comprises a developed hypoconid and smaller entoconid. An additional hypoconulid is located between both cuspids in the most distal part of the tooth in the specimens SAM-PQL-72226B and SAM-PQL-72214 ( Fig. 5C, E View Figure 5 ).
Postcranial remains: The cervical vertebrae (C1– C5) belong to two individuals ( Fig. 6 View Figure 6 ; Supporting Information, Table S2 View Table 2 ). Morphologically it is similar to Lupulella . The transverse foramen of the atlas is smaller to that of the jackal. The caudal articular process of the axis is robust. Although there is no noticeable evidence for the presence or absence of a nuchal ligament sensu Wang et al. (2008), the morphology of the back of the axis, where the ligament would attach, is similar to that of living canids with this ligament (e.g. extant jackals Lupulella mesomelas ). The axis SAM-PQL-15174 has several parallel bite marks over the spinous process, which, based on their morphology, can be interpreted as shark bites ( Fig. 6G View Figure 6 1 View Figure 1 , G 2 View Figure 2 ). Neither the transverse process nor spinous processes are preserved in the C3–C5 ( Fig. 6C–E, H View Figure 6 ). A proximal fragment of a fourth caudal vertebra is present ( Fig. 6I View Figure 6 1 View Figure 1 , I 2 View Figure 2 ).
The general morphology of the humerii and radii ( Fig. 7 View Figure 7 ; Supporting Information, Table S2 View Table 2 ) are similar to L. mesomelas than to those of African vulpini. The type SAM-PQL-31272 has bite marks of a terrestrial carnivoran on both epiphyses of these long bones. SAM-PQL-20424 is more robust and with an elongated humerus. The proximal epiphysis is known from SAM-PQL-40041 ( Fig. 8 View Figure 8 ) and the humeral head is round. The humeral diaphysis is straight, with the proximal part curved caudally and laterally compressed. It is rounded to triangular in cross-section distally. The deltoid crest is well developed ( Fig. 7A View Figure 7 1 View Figure 1 , A 2 View Figure 2 , D 1 View Figure 1 ) and the distal epiphysis is subrectangular in distal view ( Fig. 7A View Figure 7 5 View Figure 5 , B). There are two uniform facets on the lateral epicondyle: one proximally for the origin of the extensors of the carpus and digits and one distal to the origin of the m. supinator ( Munthe, 1989). There is a distinctive lateral epicondylar crest, where m. extensor carpi radialis originates ( Munthe, 1989).
The supratrochear foramen is also well developed. As in living canids, the medial epicondyle is small, where the m. pronator teres originates. The entepicondylar foramen is absent. The radii ( Fig. 7C, E View Figure 7 ; Supporting individual of L. mesomelas : F1, buccal; F2, lingual; F3, occlusal views. Scale bar 2 cm. Abbreviations: p1, definitive first lower premolar; dp2, decidual p2; dp3, decidual p3; dp4, decidual carnassial; m1, definitive carnassial.
Information, Table S2 View Table 2 ) are elongated and slightly curved caudally. The fovea capitis is oval, deep and has a cranial notch.
A small, radial tuberosity is situated on the lateral edge, where m. biceps brachii and m. brachialis attach. The shaft is craniocaudally compressed. On the first third of the laterocaudal border, the interosseous border is located. The distal epiphysis is mediolaterally large. The ulnar notch is round and small. Medially, there is a small, sharp, knob-shaped styloid process, where the m. brachioradialis inserts. In cranial view, and following the description of Munthe (1989) for borophagines canids, there are three grooves ( Fig. 7E View Figure 7 2 View Figure 2 , E 3 View Figure 3 ): a medial deep one for the tendon of the m. adductor pollicis longus, a wider lateral one for the tendon of the m. extensor digitorum communis and between them a wide and shallow groove for the tendon of m. extensor carpi radialis.
The associated postcranial skeleton of the old and pathological individual SAM-PQL-40041 ( Fig. 3C View Figure 3 ; Supporting Information, Table S2 View Table 2 ), consists of numerous fragmentary remains of the forelimb, hindlimb and axial skeleton ( Fig.8 View Figure 8 ). Several pathologies are observed, these include, notably, overgrowths of bone on the periosteal surfaces of the long bones, metacarpals, phalanges and caudal vertebrae, as well as endosteal bony growths on the IV metacarpal and radius ( Fig. 8 View Figure 8 ). These bones show bite marks, e.g. on the fragmentary scapula ( Fig. 8A View Figure 8 ). Its glenoid cavity is rounded and lateromedially wide, as in L. mesomelas , and unlike V. chama and O. megalotis .
The overall morphology of the ulna is similar to L. mesomelas , apart from the lateral and medial tubercles of the tuber olecrani. The ulna of Eucyon khoikhoi has similar morphology to V. chama , with the medial tubercle prominently larger and projected proximally, beyond the level of the lateral one. In L. mesomelas , both tubercles are similar in height. The first metacarpal is unknown. The metacarpals (II–V), carpals (magnum and pyramidal) and tarsals (ectocuneiform) are more robust compared to African vulpini, and similar to L. mesomelas and other African jackals. However, some minor traits distinguishes E. khoikhoi from L. mesomelas and other African jackals, such as the slenderer pyramidal and the wider dorsodistal part of the ectocuneiform. The phalanges ( Fig. 8E View Figure 8 1 View Figure 1 , I–K) belong to different digits, but it is difficult to determine whether they belong to the pes or manus. The size difference suggest that they belong to both. The first phalanges have a similar length to L. mesomelas and shorter to the African vulpini. They are robust, slightly straight but with ventral curvature. We cannot infer any muscular attachment because of the bone grown on the periosteal surfaces. Two of the three second phalanges are much shorter to the other, which could suggest that they are from the feet. The ungual phalanx is also relatively robust and longer, resembling to those of the living canini. The tibia (SAM-PQL-40308) only preserves a long, slender and sigmoid shaft.
Table 1. Cranial and mandible measurements of the holotype of Eucyon khoikhoi SAM-PQL-31272 from Langebaanweg. Skull measurements based on Tedford et al. (2009). Mandibles measurements based on our measurements. Abbreviations: BW, braincase width. Maximum breadth of the braincase across the level of parietal-squamosal suture; FSW, frontal shield width. Maximum breadth across the postorbital processes of the frontals; GSL, greatest skull length. Length
| Skull | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| LCM | GSL | ZW | BW | LPM | PWP4 | PWP1 | FSW | PCW | M2B | MOH | JD | LB |
| 121.1 | 152.2 | (80.2) | 51.2 | (57.2) | 24.3 | (17.1) | 40.7 | (29.2) | 33.3 | (19.0) | 8.9 | 25.8 |
| Mandible | ||||||||||||
| TL | H ascent | H ar-an | W cor | L d | Lps | Lms | L p1-ms | Hb p1 | Hb m1 | |||
| 110.3 | 42.4 | 20.0 | 21.2 | 4.4 | 35.5 | 26.4 | 61.2 | 13.9 | 14.2 | |||
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