Machairasaurus [11], the semilunate carpal protrudes between the proximal ends of metacarpals I and II, and the distal articular facets are angled away from each other. Three carpals are visible in the left hand. One is presumably the semilunate carpal but it is partially obscured by matrix. It has drifted a few millimeters away from the metacarpus, and therefore was clearly not fused to it. The semilunate carpal often fuses with the first two metacarpals in oviraptorids, including specimens of Heyuannia [19] and Ingenia (MPC-D 100/30). This is clearly an age related phenomenon, and fusion may have occurred in larger specimens of Nemegtomaia. The second carpal is a small, round bone positioned between the distal ends of the ulna and radius. The identity of the third carpal is uncertain because it is small, round and featureless, and has drifted out of position to lie on the proximodorsal surface of the first metacarpal. The metacarpus is well preserved in both hands. The first metacarpal is slightly more than half the length (52%) of the second metacarpal, which is comparable with Conchoraptor (58% in MPC-D 100/38), Heyuannia [19], Ingenia (69% in MPC-D 100/30), and Machairasaurus (63% in IVPP 15979). The percentage is less than fifty in other oviraptorids. Even though it is shorter than the other metacarpals, the shaft of metacarpal I is 50% thicker than that of metacarpal II, and is four times thicker than the shaft of metacarpal III. The same shaft thickness ratios are slightly less in Ingenia (1.38 for McII and 2.93 for McIII in MPC-D 100/33) and Heyuannia [19]. The proximal end of the first metacarpal is divided into a large proximolaterally oriented facet for contact with the semilunate carpal and a smaller proximomedially facing surface. Metacarpal III is about 90% the length of McII. However, its proximal end is more distal in position than that of McII; consequently, the distal end of McIII almost reaches the distal end of McII. The proximal end of metacarpal III is also separated from the carpus in Heyuannia [19], Khaan [39], and Machairasaurus [11]. The shafts of metacarpals II and III are closely appressed as in other oviraptorids. As in MPC-D 107/15, the shaft of the third metacarpal is reduced to a splint. The first digit is almost as long as the second digit, with the tip of the first ungual reaching mid-length the second ungual, as it does in the articulated hand of MPC-D 107/15. In comparison, Citipati, Khaan and Machairasaurus each have a first ungual that extends to the end of the penultimate phalanx of digit II, whereas in Ingenia the tip of the first ungual reaches the same level as the tip of the second one. The first phalanx of the first manual digit is robust, and is about 40% thicker than the first phalanx of the second digit. In Heyuannia and Ingenia, manual phalanx I-1 is double the diameter of phalanx II-1. In the second digit of MPC-D 107/15, the combined lengths of phalanges II-1 and II-2 equal 29.5 mm, which is shorter than the length (34 mm) of the second metacarpal (87%). This is also true for Ingenia (MPC-D 100/30, 78%; MPC-D 100/31, 76%; MPC-D 100/33, 77%) and Heyuannia [figure 13.4 in 19], in which the sum of the lengths of these two phalanges is about the same as the length of the associated second metacarpal; in all other oviraptorosaurids, the sum is greater. Phalanx II-2 is shorter than phalanx II-1, which is similar to the situations in Heyuannia, Ingenia and Machairasaurus; in most of the other oviraptorids, phalanx II-2 is longer than phalanx II-1. The third digit of the right hand, except for the base of the first phalanx, was destroyed by erosion. There are at least two small phalanges on the third digit of the left hand, but the distal end of the second one is incomplete. In the left hand of MPC-D 107/15, and both hands of MPC-D 107/16, III-1 is less than two thirds the length of II-1 and almost half its diameter. Only the anteroventral corner of the preacetabular process of the ilium is preserved, but it is similar to the shape of those parts of the ilia of the holotypes of Nemegtomaia and Ingenia. New Specimens of Nemegtomaia from Mongolia The femora are almost complete and as preserved are up to 21 cm long. Using the transverse shaft width and the same regression that was used for MPC-D 107/15, the calculated length of the femur is 222 mm. Phylogenetic analysis Phylogenetic analysis was performed by adapting the matrix of Longrich et al. [11] and using the exhaustive search algorithm of PAUP* 4.0b10 [59] (Figure 8) (Tables S1, S2, and S3). Velociraptor was used as the outgroup for the Oviraptorosauria, Avimimus was used as the outgroup for the Oviraptoridae, and taxa (Chirostenotes, Gigantoraptor, Incisivosaurus and Nomingia) were excluded if fewer than 50% of the 183 characters (Table S2) were coded. Heyuannia, Machairasaurus and Oviraptor, also had fewer than 50% of the characters coded, but were left in because they are part of the ingroup being analyzed. The subset included twelve taxa (Avimimus portentosus, Citipati osmolskae, Citipati n.sp. (MPC-D 100/42, also referred to in other analyses as ‘‘Oviraptor philoceratops’’ or the Zamyn Khondt [ = Dzamyn Khond] oviraptorid), Conchoraptor gracilis, Heyuannia huangi, Ingenia yanshini, Khaan mckennai, Machair- asaurus leptonychus, Nemegtomaia barsboldi, Oviraptor philoceratops, Rinchenia mongoliensis and Velociraptor mongoliensis). Three characters are ordered, and the remaining ones are unordered. All characters have equal weight. A total of 654,729,075 trees were evaluated to produce two most parsimonious trees of length 210 (consistency index of 0.867, a retention index of 0.731 and a rescaled consistency index of 0.633). The only difference between the two trees is that Oviraptor clustered in one tree with Rinchenia mongoliensis, Citipati osmolskae and Citipati n.sp. in a monophyletic Oviraptorinae, whereas in the other tree Oviraptor was the sister to all other oviraptorids. The Ingeniinae includes (Khaan+(Conchoraptor+ (Machairasaurus+(Ingenia+(Heyuannia+Nemegtomaia))))). Robustness was determined using bootstrap (1000 replicates) and decay indices (Fig. 8). All ingroup nodes have decay values greater than 1, and are still present in the strict consensus of all trees either one or two steps beyond the Most Parsimonious Tree. With the exception of Oviraptor, all bootstrap values within the Oviraptoridae have high bootstrap values (greater than 75%). In all runs of the phylogenetic analysis, Nemegtomaia is shown to be one of the most derived ingeniine oviraptorids, and is most closely related to Ingenia and Heyuannia. The original analysis by Lu et al. [14] recovered Nemegtomaia as an oviraptorine oviraptorid closely related to Citipati osmolskae, thereby demonstrating that the additional anatomical information from the new specimens significantly improves our understanding of oviraptorid systemat- ics (Figure 8). Some of the characters in the Longrich et al. [11] matrix rely on ratios of bones that are incomplete in MPC-D 107/15, and to code the characters, missing dimensions were calculated from the parts of the bones that are preserved. Five of these characters (130, 134, 136, 138, 139) were coded, and may have unduly influenced the results. Because this is a potential source of error, the five characters were rescored as unknown for Nemegtomaia, and the analysis was rerun. This time the phylogenetic analysis was performed using the heuristic search algorithm of PAUP* 4.0b10 [59] using 1000 replicates, and once again the analysis produced two most parsimonious trees with tree lengths of 210. The consensus tree topology is identical to that of the previous analysis, the CI remained the same at 0.867, and the RI is slightly less at 0.728. With the exception of Oviraptor, all bootstrap values (1000 replicates) within the Oviraptoridae still have high bootstrap values, although each dropped in value by 2 to 4%. PLoS ONE | www.plosone.org 10 February 2012 | Volume 7 | Issue 2 | e31330