Nambashag microglaucus, Worthy, 2011

Worthy, Trevor H., 2011, Descriptions and phylogenetic relationships of a new genus and two new species of Oligo-Miocene cormorants (Aves: Phalacrocoracidae) from Australia, Zoological Journal of the Linnean Society 163 (1), pp. 277-314 : 292-299

NAMBASHAG MICROGLAUCUS SP. NOV. ( FIG. 3 )

Holotype: SAM P.32584, right femur.

Diagnosis: A species of Nambashag with femur about 30% shorter than that of Na. billerooensis , and smaller than all Microcarbo species with the humeral proc. supracondylaris dorsalis relatively large with its tip proximal to the condylus dorsalis, the tuber. supracondylare ventrale rotated ventrally, and on the femur, the sulcus for the M. flexor hallicus longus extending into the cranial half of craniocaudal femur depth.

Etymology: Latin, micro for very small, and glaucus, after the Greek mythological fisherman Glaucos.

Type locality: Site 2, Billeroo Creek, Frome Downs Station, South Australia, Australia 31°06.205 ′ S, 140°13.912 ′ E, collected THW & A. Camens 5–6.vi.2007 .

Stratigraphy/age/fauna: Namba Formation, Late Oligocene 24–26 Mya, Namba LF.

Distribution: Late Oligocene (24–26 Mya), South Australia, Australia: Billeroo Creek, Namba Formation; Lake Palankarinna, Etadunna Formation, Minkana LF, Zone A.

Measurements of holotype: Length 38.8 mm, proximal width 10.4 mm, mid shaft width 4.0 mm, mid shaft depth 4.4 mm, maximum distal width 9.5 mm.

Paratypes: Site 2 Billeroo Creek, Frome Downs Station , South Australia, 31°06.205 ′ S, 140°13.912 ′ E, Namba Formation, Late Oligocene, all collected THW & A. Camens 5–6.vi.2007 – SAM P. 32586, distal R humerus; SAM P. 32587, distal L humerus; SAM P.32588, proximal L ulna; SAM P.32585, distal R femur; SAM P.32582, dL tibiotarsus; SAM P.32583, distal + shaft R tibiotarsus.

Referred material: 2 Site 31°06.205 ′ S, 140°13.912 ′ E, Billeroo Creek, Frome Downs Station, South Australia, Namba Formation, Late Oligocene, all collected THW & A. Camens 5–6.vi.2007 – SAM P.32590, sternal end L coracoid; SAM P.32591, cranial part L scapula; SAM P.32589, distal R radius. Billeroo Creek, Frome Downs Station , South Australia, map grid coordinates 319151 (CURAMONA SH 54–14, provisional ed. 1964, Series R502 , 1 : 250 000, 1973 reprint), Namba Formation, Late Oligocene, collected T. H. Rich 7.ix.1977 ( THR 1977–206 ) – MV P.222426, sternal end R coracoid. Billeroo Creek, ‘ Site 3’ (collection code QMAM 199 ) , R. Tedford et al. 1971 – AMNH 10782 , R tarsometatarsus lacking all trochlea. Neville’s Nirvana, Lake Palankarinna, South Australia, Etadunna Formation, Zone A, Late Oligocene, Minkana LF, collected 20.viii.1997 by J. McNamara , South Australia Museum – SAM P.41274, distal L tibiotarsus.

Description: Femur (holotype SAM P32584, SAM P.32585; Fig. 3A–C ). The holotype is essentially perfect, although was reassembled from two pieces and is a pale brown colour. For measurements, see Measurements of holotype. It is generally similar to phalacrocoracids and differs from Na. billerooensis by considerably smaller size and qualitative features as follows. The insertion of the M. psoas is prominent and located closer to the medial side of the cranial facies (70); the caudal facies below the facies antitrochanterica lacks a broad fossa (74); the sulcus for flexor hallicus longus proximal to the trochlea fibularis is more deeply excavated, extending into the cranial half of bone depth (77); the condylus lateralis on the caudal facies terminates in a rounded protuberance proximally (78) rather than a narrow crest; in caudal aspect, the condylus lateralis is widest proximally and narrows slightly distally (79), rather than widening distally in Anhinga .

Tibiotarsus ( SAM P.32582, SAM P.32583, SAM P.41274; Fig. 3D ). Only the distal end and the shaft from mid way down the crista fibularis is known, as exemplified best by SAM P.32583. Measurements: SAM P.41274, a distal fragment 17 mm long, distal width 7.0 mm, depth condylus lateralis 7.0 mm, depth condylus medialis 8.1 mm; SAM P.32583 preserved length 34.8 mm, shaft width through crista fibularis 6.0 mm, minimum shaft width 4.0 mm, distal width 8.3 mm, depth condylus lateralis 6.9 mm, depth condylus medialis 8.0 mm. The element differs from that of Na. billerooensis as follows: it is significantly smaller; has a more flattened anterior facies with a strongly angled anteromedial edge; and the tuber. retinaculi M. fibularis is raised anteriorly bounding a shallow sulcus between it and the sulcus extensorius (91).

Tarsometatarsus ( AMNH 10782; Fig. 3E–H ). This R tarsometatarsus lacks all three trochlea but preserves the entire foramen distale, and also lacks the medial hypotarsal ridge plantar of the tendinal canal for M. flexor digitorum longus (fdl), which is completely enclosed. The tendinal canal for M. flexor hallicus longus (fhl) is partly preserved, but laterally of it the surface is broken or worn, as is the lateral facies of the ridge bounding fdl, so the extent of or presence of bone surrounding the fhl plantarly is not known. The fdl is offset plantarly from fhl as in all crown phalacrocoracids. The length of the medial hypotarsal ridge is proximodistally very short, so that in medial view, even though the plantar facet is lost, the remaining crest shows that the plantar facet can only have extended distally a distance equivalent to level with the distal extent of the anterior lip of the condylus medialis, compared to Microcarbo taxa where it extends considerably further distally. Measurements: preserved length 27.5 mm, estimated total length 30 mm, proximal width 7.5+ mm (slightly worn laterally), minimum shaft width 3.8 mm, shaft depth 2.6 mm. Apart from its much smaller size, this species differs from Na. billerooensis as follows: the sulcus for M. abductor digiti IV is bound by the crista plantaris lateralis dorsally only in the proximal half of the bone, as distally neither a sulcus nor a crista is present; the sulcus extensorius is proximally deep and centred on the shaft, but rapidly shallows distally such that shaft is anteriorly convex adjacent sulcus for M. extensor hallicus longus, i.e. proximal to the mid-point; and the metatarsal facet is large and prominent medially.

Coracoid ( MV P.222426; SAM P.32590). These two sternal parts of coracoids are referred on the basis of their size. Measurements: MV P.222426 preserved length 20.4 mm, shaft width 2.6 mm; SAM P.32590 preserved length 22.5 mm, shaft width 2.9 mm. They show that the angulus medialis is acute; a distinct sulcus on the ventral facies; the linea M. ventralis joins the facies artic. sternalis ventralis in lateral half; dorsally, a ridge links to the facies artic. sternalis close to the medial angle enclosing a broad shallow fossa laterally; and the facies artic. sternalis dorsalis has only a shallow lip enclosing it cranially in its medial half, one not as prominent as in Na. billerooensis .

Scapula ( SAM P.32591). Referred on the basis of appropriate size, this specimen has a preserved cranial width of 8.9 mm, and shaft dorsoventral depth of 3.8 mm.

Humerus ( SAM P.32586, SAM P32587; Fig. 3I ). Measurements: SAM P.32586 preserved length 14.1 mm, distal width 7.8 mm, maximum distal depth 6.1 mm, SAM P.32587 preserved length 16.0 mm, distal width 7.8 mm, maximum distal depth 6.1 mm. These were referred on the basis of size and association with other elements. They have the typical phalacrocoracid shape of a narrow deep distal end; condyles with similar cranial projection; dorsal facies and epicondylus ventralis roughly parallel and at right angles to ventrodorsal plane; fossa olecrani large and deep, bound by a dorsoventrally narrow proc. flexorius; and sulcus scapulotricipitalis well defined and about half the width of the sulcus humerotricipitalis, which as in crown phalacrocoracids, has a low median ridge. Apart from very small size they differ from humeri of Na. billerooensis as follows: the tuber. supracondylare ventrale is orientated ventrally (39); the proc. supracondylaris dorsalis is relatively large and its tip is proximal to the proximal side of the condylus dorsalis (41), unlike in crown phalacrocoracids and Na. billerooensis ; the fossa M. brachialis ends distally proximal to the tuber. supracondylare ventrale, as in Anhinga , whereas it overlaps the tuberculum in Na. billerooensis and other phalacrocoracids examined.

Ulna ( SAM P.32588; Fig. 3J, K ). Referred on the basis of size and that the cotyla dorsalis is not hooked distally. Measurements: proximal width 5.9 mm, dorsoventral shaft width 3.3 mm. The cranial facies is flat and meets the impressio brachialis in a right angle; the olecranon is low and does not extend proximal to the cotyla ventralis; the impressio brachialis is not deeply excavated proximocaudally, as it is in Na. billerooensis ; the attachment of M. bicipitis below the cranial lip of the cotyla ventralis is ovate and low; and the incisura radialis is a discrete sulcus, bound dorsally by a ridge leading to the cotyla dorsalis.

Radius ( SAM P.32589). Referred on the basis of appropriate size, this specimen has a maximum distal width of 5.0 mm.

Comparisons with fossil taxa

Nambashag microglaucus is smaller than all crown group phalacrocoracids. It is even smaller than Limicorallus saiensis , which has a distal humerus width of 8.6 mm. Although both taxa are similar in that the fossa m. brachialis ends proximal to the tuber. supracondylare ventrale, L. saiensis differs from Na. microglaucus by a less elongate tuber. supracondylare ventrale and having the tip of the proc. supracondylare dorsalis level with the proximal side of the condylus dorsalis, not proximal of it.

PHYLOGENETIC ANALYSES

Parsimony analyses

In an initial analysis, in which Phaethon was included with Pelecanus and Fregata in the outgroup, both Nambashag species and Microcarbo niger were included, and all characters treated as unordered and given equal weight, a strict consensus of 520 most parsimonious trees [MPTs; length 468, consistency index (CI) = 0.3483, homoplasy index (HI) = 0.6517, retention index (RI) = 0.6670] was relatively poorly resolved. The outgroup taxa formed a polytomy with sulids, anhingids, and a clade of all cormorants. Within this last clade of cormorants, the three fossil taxa formed a polytomy with a clade of extant taxa. Amongst the extant taxa, the Microcarbo taxa formed a clade sister to remaining cormorants.

Reduced taxon set, all characters unordered, equally weighted: Phaethon is no longer considered particularly closely related to pelecaniforms (e.g. Hackett et al., 2008), so any homoplasy between it and pelecaniform taxa is likely to unduly affect the polarity of characters. Because of this, and that Microcarbo niger and Na. microglaucus were missing substantial data (74 or 65% of characters in the latter), these three taxa were deleted from this and subsequent analyses. With Pelecanus , Fregata , and the sulids designated as the outgroup, and all characters treated as unordered and with equal weight, a heuristic search found 137 MPTs (length 430, CI = 0.3698, HI = 0.6302, RI = 0.6691) for which the strict consensus tree was well resolved ( Fig. 4 ). Pelecanus and the sulids formed a clade, but with no significant bootstrap support, which with Fregata and a clade of all remaining taxa formed a polytomy. This clade of anhinga species and cormorants had 76% bootstrap support. The two Anhinga species formed a well-supported clade (99%) that was the sister group of an equally well-supported clade (99%) of all cormorants including the fossil taxa. The fossil cormorants Nectornis and Na. billerooensis were successive sister groups to a clade of all extant taxa (84%), amongst which Microcarbo taxa (94%) were sister to a poorly resolved and less wellsupported clade of remaining taxa (79%). Within the nonmicrocarbine taxa, only three clades received significant support: (1) P. feathersoni + P. punctatus (80%); (2) P. urile + P. pelagicus (97%); (3) and all Leucocarbo taxa (77%).

Reduced taxon set, 19 characters ordered, all characters equally weighted: In an effort to obtain greater resolution of extant phalacrocoracids the effects of ordering a set of 19 characters (* in Appendix 1) that varied as morphoclines was assessed and 36 MPTs (length 437, CI = 0.3638, HI = 0.6362, RI = 0.6844) gave a strict consensus tree that was similarly well resolved as Figure 4 . In this tree (not presented here), the outgroup taxa had the same relationship sister to a clade of anhingas and cormorants as previously. The main change in the topology was that the pairing of P. punctatus and P. featherstoni disassociated from the taxa P. pelagicus + P. urile + P. aristotelis + P. gaimardi + P. pencillatus , with which it had previously associated, and moved to a position sister to those taxa plus all Leucocarbo taxa.

Reduced taxon set, all characters unordered, pelvic girdle characters weighted 0.5: The effect of weighting the pelvic girdle characters with all characters unordered was assessed. A strict consensus of 58 MPTs (length 325.5, CI = 0.3840, HI = 0.6160, RI = 0.6789) was more poorly resolved than in previous analyses (tree not presented here), but retained all clades with significant bootstrap support in the unordered + equally weighted analysis given in Figure 4 .

Reduced taxon set, 19 characters ordered, pelvic girdle characters weighted 0.5: In an analysis, where both ordering was imposed on 19 characters and pelvic characters weighted 0.5, 37 MPTs (length 331.0, CI = 0.3776, HI = 0.6224, RI = 0.6898) gave a strict consensus tree that was also poorly resolved. As in the tree derived from the unordered/weighted analysis ( Fig. 4 ), this tree also had all the clades with bootstrap support found in the unordered + equally weighted analysis.

Topology constrained so P. gaimardi sister to extant taxa other than Microcarbo: Because molecular data indicate that P. gaimardi is sister to all extant taxa other than those in Microcarbo (see above) and the above analyses found little support for the arrangement of taxa/clades in this group, the analysis was constrained as detailed in the Methods. This made P. gaimardi sister to remaining extant taxa other than Microcarbo , yet enforced no branching order on any of those taxa, and importantly allowed the fossil taxa to associate as the data indicated. With all characters unordered and equally weighted, 456 MPTs (length 436, CI = 0.3647, HI = 0.6353, RI = 0.6618) gave a strict consensus tree that was fairly well resolved. In this, the basal topology was the same as in previous analyses, but sister to P. gaimardi , three clades were obtained as follows: (1) all Leucocarbo taxa + P. pencillatus ; (2) [( P. pelagicus + P. urile ) ( P. aristotelis + P. neglectus )] + ( P. featherstoni + P. punctatus ); (3) remaining taxa.

When constrained so that analyses were forced to make P. gaimardi sister to phalacrocoracids other than Microcarbo species , ordering was imposed on 19 characters, and pelvic characters were weighted 0.5, much of the conflict was removed and only three MPTs were found that were just two steps longer than the equivalent unconstrained analysis (length 332.0, CI = 0.3765, HI = 0.6235, RI = 0.6883) for which the strict consensus is very well resolved ( Fig. 5 ). The only difference from the previous analysis is that P. aristotelis + P. neglectus moved from Clade 2 to become sister to P. penicillatus . This tree has higher consistency and retention indices and a lower homoplasy index, so is my favoured hypothesis for assessing the relationships of the fossil taxa.

In this analysis, although the ingroup is strongly supported as monophyletic (90% bootstrap support), there is no support for the internal relationships of the outgroup taxa sulids, Fregata and Pelecanus . Within the ingroup, Anhinga species formed a strongly supported clade (99%) sister to a similarly well-supported (99%) clade of all cormorants, including Nambashag and Nectornis . Within cormorants, Nambashag was sister to a clade of Nectornis and all extant cormorants, with moderate support (68%). Extant cormorants formed a well-supported clade (91%), within which Microcarbo taxa (97%) were sister to the rest (98%). Of the remaining taxa, support for P. gaimardi being sister to a monophyletic clade of all other taxa was high (80%). However, within this clade that was sister to P. gaimardi , only four clades had significant support: (1) P. urile + P. pelagicus (98%), (2) a poorly resolved clade of all Leucocarbo taxa (88%), (3) P. punctatus + P. featherstoni (74%), and (4) a more weakly supported (62%) group ( P. carbo , P. capensis , P. sulcirostris , P. varius , P. fuscescens , P. nigrogularis , P. brasilianus , and P. auritus ).

To summarize, these analyses reveal strong support for recognition of the superfamily Phalacrocoracoidea for the anhingids and the phalacrocoracids. The fossil taxa, Nambashag and Nectornis , are shown to be stem members of crown group Phalacrocoracidae , with no evidence that they could be on the stem of Phalacrocoracoidea . Amongst crown group phalacrocoracids, Microcarbo taxa were sister to remaining phalacrocoracids. Within the latter, significant support was found for a basal position for P. gaimardi , and for a clade of all Leucocarbo taxa.

Interpretations of phylogenetic analysis

Using the analysis in which P. gaimardi was constrained to be consistent with genetic evidence, 19 characters were ordered and pelvic characters weighted, optimization of characters revealed the following apomorphies for various clades and taxa ( Fig. 5 ).

Nambashag billerooensis, Ne. miocaenus , and all recent phalacrocoracids form a clade (A), which is sister to Anhinga , supported by 42 apomorphic changes, of which 12 are unambiguous, as follows: humerus with a deep fossa pneumotricipitalis ventralis (char. 31: 0 => 1, CI = 1.000); humeral proc. flexorius has equal or greater prominence than the epicondylus ventralis (char. 40: 0 => 1, CI = 0.500); humeral proc. supracondylaris dorsalis is located distal to the proximal margin of the condylus dorsalis (char. 41: 0 => 1, CI = 1.000), although Na. microglaucus is primitive for this character; the ulnar tuber. collateralis ventralis is not ventrally prominent of the cotylar margin (char. 44: 0 => 1, CI = 0.500); the ulnar tuber. collateralis ventralis is elongate and separated from the cotylar margin (char. 45: 0 => 1, CI = 0.500); on the carpometacarpus, the trochlea carpalis ventralis joins the shaft markedly distal to the proc. pisiformis (char. 53: 0 => 1, CI = 1.000); on the coracoid, the protuberant boss on the cranial margin of the facies artic. sternalis dorsalis occupies no more than half the total width of the articular facet (char. 61: 0 => 1, CI = 1.000); on the femur, the tuber. gastrocnemialis lateralis is elongate and distinctly separated from the trochlea fibularis (char. 76: 0 => 1, CI = 1.000); on the tarsometatarsus, the dorsoplantar depth is greater than proximal width (char. 99: 0 => 1, CI = 0.500); the hypotarsus has a distinct hook (char. 102: 0 => 1, CI = 0.250); the trochlea metatarsi IV extends equal to or distally of the groove in the end of trochlea metatarsi III (char. 109: 0 => 1, CI = 0.200); and the dorsal width of trochlea metatarsi IV is less than or equal to its length (char. 110: 0 => 1, CI = 0.500).

Nambashag billerooensis is defined by seven unambiguous apomorphies as follows: mandible with area below cotyla medialis and caudad of the fossa aditus canalis mandibulae deeply concave (char. 26: 0 => 1, CI = 0.167); mandible with fossa aditus canalis mandibulae large and deep, extending close to the ventral side of mandible, with no caudal pocket (char. 27: 0 => 2, CI = 0.500); carpometacarpus with elongate proximal synostosis of os metacarpale majus et minus (char. 47: 1 => 0, CI = 0.250); carpometacarpus with fovea carpalis caudalis short and wide (char. 49: 1 => 0, CI = 0.250); coracoid with cotyla scapularis a shallow depression (char. 59: 1 => 0, CI = 0.500); femur with the sulcus for M. flexor hallicus longus emarginated dorsally and restricted to caudal half of shaft (char. 77: 0 => 1, CI = 0.231); and tarsometatarsus with tendinal canal for M. flexor digitorum longus not enclosed laterally (char. 96: 1 => 0, CI = 0.400).

Nambashag billerooensis is excluded from a clade of extant phalacrocoracids and Ne. miocaenus (clade B) by retention of the plesiomorphic state for five unambiguous apomorphies as follows: humerus with long crista deltopectoralis (char. 34: 0 => 1, CI = 0.500); humerus with cranially directed tuber. supracondylare ventrale, not partly ventrally (char. 39: 0 => 1, CI = 1.000); ulna with the proc. cotyla dorsalis not markedly hooked distally (char. 43: 0 => 1, CI = 1.000); femur with insertion for the M. psoas centred on the cranial facies, not closer to the medial side (char. 70: 0 => 1, CI = 0.167); and tarsometatarsus with the tendinal canal for M. flexor hallicus longus enclosed plantarly, not open (char. 97: 0 => 1, CI = 0.500). Further, retention of a wide groove for the tendinal canal for M. flexor hallicus longus, where it crosses the dorsomedial margin of the shaft, rather than a narrow groove as in all other phalacrocoracids, appears significant (char. 101: 0 –> 1, CI = 0.667), but this is rendered ambiguous by convergence in Sula .

Nectornis miocaenus is excluded from crown group Phalacrocoracidae (clade C) by the plesiomorphic state for nine unambiguous apomorphies of which the most compelling are: humerus with impressio coracobrachialis with a poorly defined or rounded ventral margin rather than with a crest (char. 37: 0 => 1, CI = 0.667); ulna with cranial projection of the distal condylus ventralis ulnaris only slight, not great (char. 46: 1 => 2, CI = 1.000); coracoid with no excavation in the sulcus M. supracoracoidei below the ridge linking the facies artic. humeralis and the proc. acrocoracoideus (char. 57: 0 => 1, CI = 0.333); coracoid with lateral facies of proc. acrocoracoideus sternally of impressio lig. acrocoracohumeralis with shallow not deep groove (char. 58: 0 => 1, CI = 0.333); tibiotarsus with the thickened proximolateral tip of the crista cnemialis lateralis grading into the crista medially rather than offset proximally (char. 85: 0 => 1, CI = 0.667); tibiotarsus with tip of crista cnemialis lateralis overlapping facies artic. lateralis in proximodistal plane (char. 86: 0 => 1, CI = 0.500); and tibiotarsus with distal condyles with near equal distal extent (char. 93: 0 => 1, CI = 0.500). In addition, the femur has the linea intermuscularis caudalis present as a short ovate crista near the nutrient foramen and separated by a wide gap from the crista for M. flexor ischiofemoralis more proximally, rather than by a short gap, or not separated (char. 75: 0 –> 1, CI = 0.500), a character rendered ambiguous by P. gaimardi , alone of crown group Phalacrocoracidae , having the same plesiomorphic state. This is support for the relatively basal position of P. gaimardi as sister to phalacrocoracids except Microcarbo as determined by genetic data ( Kennedy et al., 2009).

Microcarbo (clade D) is supported by eight unambiguous apomorphies as follows: cranium with ventrally directed anterior facies of palatine process of os lacrimale excavated into a shallow fossa (char. 4: 0 => 1, CI = 0.500), convergent with Leucocarbo ; cranium with a very narrow fossa temporalis (char. 11: 0 => 2, CI = 0.500); palatines unfused (char. 14: 1 => 2, CI = 0.500); premaxilla shorter than cranium length (char. 19: 0 => 1, CI = 0.500); carpometacarpus with elongate proximal synostosis of os metacarpale majus et minus (char. 47: 1 => 0, CI = 0.250); carpometacarpus with fovea carpalis caudalis short and wide (char. 49: 1 => 0, CI = 0.250); tibiotarsus with least proximodorsal width of pons supratendineus equal to or greater than width of the sulcus extensorius proximal to the pons (char. 95: 1 => 0, CI = 0.250); and tarsometatarsus with lateral margin distal of the foramina vascularia proximalia planar (char. 105: 1 => 0, CI = 0.500).

Microcarbo is excluded from remaining crown group phalacrocoracids (clade E) by retention of the plesiomorphic state for 13 unambiguous apomorphies of which the most compelling are: retention of small impressio glandulae nasalis (char. 5: 0 => 1, CI = 0.400); mandible, elongate separation of processus coronoideus from cotyla lateralis (char. 29: 0 => 1, CI = 0.333); tibiotarsus with thickened proximolateral part of the crista cnemialis lateralis only slightly offset from the medial part of this crista, not in line or distinctly offset (char. 85: 1 => 2, CI = 0.667); distal extent of trochlea metatarsi II surpasses or is near equal to trochlea metatarsi III, not proximal to (char. 108: 0 => 1, CI = 0.333).

The relatively basal position of P. gaimardi is supported by retention of the plesiomorphic state for four unambiguous apomorphies that define remaining taxa (clade F) as follows: absence of a second pair of post-orbital processes anterior to fossa temporalis (char. 13: 0 => 1, CI = 0.400); mandible with very small dorsally located fossa aditus canalis mandibulae with a caudal pocket (char. 27: 0 => 2, CI = 0.500); femur has the linea intermuscularis caudalis present as a short ovate crista near the nutrient foramen and separated by a short gap from the crista for M. flexor ischiofemoralis more proximally, rather than not separated (char. 75: 1 => 2, CI = 0.500); and tibiotarsus with impressio lig. collateralis medialis formed from two distinct well separated insertions, one for the M. flexor cruris lateralis and a more elongate one for M. flexor cruris medialis nearer the cranial margin (char. 88: 0 => 1, CI = 0.667).

Leucocarbo (clade G) is supported by five unambiguous apomorphies of which the most compelling are: cranium with ventrally directed anterior facies of palatine process of os lacrimale excavated into a shallow to deep fossa (char. 4: 0 => 1, CI = 0.500); humerus, dorsal margin of the intumescentia dorsally convex and overhanging or protuberant over the proximal half of the impressio coracobrachialis (char. 38: 0 => 1, CI = 1.000); tibiotarsus with the fossa flexoria divided such that the medial portion is equal to or wider than the lateral portion (char. 87: 1 => 2, CI = 0.333); and foot colour pink (char. 114: 0 => 1, CI = 0.500), convergent in Fregata .

Figures

Figure 3. Nambashag microglaucus sp. nov.: Right femur (SAM P.32584), holotype, in caudal (A), anterior (B), and lateral (C) views; distal right tibiotarsus (SAM P.32583) in cranial view (D); right tarsometatarsus (AMNH 10782) in dorsal (E), medial (F), lateral (G), and plantar (H) views; distal left humerus (SAM P.32587) in cranial aspect (I); proximal left ulna (SAM P.32588) in ventrocranial (J) and cranial (K) aspects. Scale bars = 10 mm. Abbreviations: fb, fossa M. brachialis; col, condylus lateralis; com, condylus medialis; ehl, groove for the M. extensor hallicus longus; fdl, tendinal canal for M. flexor digitorum longus; fhl, tendinal canal for M. flexor hallicus longus; fmI, fossa metatarsi I; fvd, foramen vasculare distale; hyp, hypotarsus; ir, incisura radialis; Mc, insertion for M. caudofemoralis; Mfhl, origin for M. flexor hallicus longus; Mfi, insertion for M. flexor ischiofemoralis; Mp, insertion for M. psoas; pcd, proc. cotyla dorsalis; psd, proc. supracondylaris dorsalis; saIV, sulcus for M. abductor digiti IV; tcv, tuber. lig. collateralis ventralis; trf, tuber. retinaculi M. fibularis; tsv, tuber. supracondylare ventrale.

Figure 4. A strict consensus tree of 137 most parsimonious trees, length 430, from parsimony analysis of the reduced taxon set, with all characters unordered and equally weighted. Bootstrap values (1000 replicates) greater than 50% shown above branches.

Figure 5. A strict consensus of three most parsimonious trees from analysis in which Phalacrocorax gaimardi was constrained to be sister to non-Microcarbo taxa, ordering applied to 19 characters, and weighting of 0.5 to pelvic characters. Bootstrap values (1000 replicates) where greater than 50%, are shown above nodes. Letters A-G indicate major clades discussed in the text.