Conservation implications of a new fossil species of hopping-mouse, Notomys magnus sp. nov. (Rodentia: Muridae), from the Broken River Region, northeastern Queensland

Figures & data

Figure 1. Locality map, highlighting the study site and other sites mentioned in text (modified from Breed & Ford, 2007 and the Atlas of Living Australia (https://www.ala.org.au/). the type locality for Notomys longicaudatus is the Moore River in southwestern Western Australia.

Figure 2. Diagrammatic representation of M^1-3 of Notomys magnus sp. nov., showing Notomys molar terminology used throughout the text. Cusp terminology follows Musser et al. (2005).

Figure 3. Notomys magnus sp. nov. A, QM F55835. Holotype. Left maxilla in left lateral view. B, The same in dorsal view, highlighting the proximal part of the zygomatic arch. Red arrows point to the broken part of the zygomatic arch, indicating the presence of additional missing bone from which it is inferred that the overall thickness of the anterior zygomatic arch would have been thicker.

Figure 4. Notomys magnus sp. nov. A, QM F55835. Holotype. Left maxilla with M^1-3. B–D, SEMs of M¹, M² and M³ of holotype QM F55835. E, QM F55832. SEM image of left upper first molar (M¹); F, QM F60725. Left M¹. G, H, QM F60723. Associated left maxilla fragments with M¹ (G) and M^2-3 (H). I, J, QM F60724. Associated left maxilla fragments with M^1-2 (I) and M³ (J). Red bars indicate the positions of the incipient anterior lingual cusps on M1s. All scale bars equal 1 mm.

Figure 5. Comparison between the maxillae of two Notomys species. A, N. magnus sp. nov. from the Broken River region. B, Notomys longicaudatus from Mount Etna (see Fig. 1). Note the well-developed buccal cusps of N. magnus and the relatively narrow posterior lophs of M^1-2 of N. magnus, compared with those of N. longicaudatus. Scale bars equal 1 mm.

Table 1. Molar (M^1-3) and zygomatic plate measurements for the examined specimens of Notomys magnus sp. nov.

		M^1		M^2		M^3		TMR	ZP
Specimen #	Description	L	W	L	W	L	W	L	L
QM F55835	Left maxilla	3.01	2.18	2.11	1.92	1.6	1.13	6.57	4.46
QM F55832	Left M^1	2.98	2.17
QM F60723	Left maxilla	3.05	2.1	2.15	1.88	1.6	1.17	6.71
QM F60724	Left maxilla	2.96	2.1	2.04	1.76	1.61	1.28	6.52	4.18
QM F60725	Left M^1	3.08	2.36

Abbreviations: L, length; W, width; TMR, total molar row; ZP, zygomatic plate. All measurements are in mm.

Table 2. Measurements of range, mean and standard deviation for upper molar dimensions for Notomys magnus sp. nov.

n	Description	Range	Mean	STDV
5	M^1 L	2.96–3.08	3.016	0.049295
5	M^1 W	2.1–2.36	2.182	0.106395
3	M^2 L	2.04–2.15	2.1	0.055678
3	M^2 W	1.76–1.92	1.853333	0.083267
3	M^3 L	1.6–1.61	1.603333	0.005774
3	M^3 W	1.4–1.53	1.45	0.07
2	ZP L	4.18–4.46	4.32	0.19799
3	TMR	6.52–6.71	6.6	0.098489

Abbreviations: n, number of specimens; L, length; W, width; TMR, total molar row; ZP, zygomatic plate. All measurements are in mm.

Figure 6. Plot of log mean mass against log mean total molar row (length) to estimate the mass of Notomys magnus sp. nov. Data for Notomys cervinus and Notomys fuscus from Tate (1951), Notomys aquilo, Notomys mitchellii and Notomys amplus from Mahoney et al. (2007) and Notomys longicaudatus from Thomas (1921). Horizontal dashed line indicates the lower limit of the CWR (see text). Dental measurements for Notomys alexis were not clearly reported in literature and since it is a small-bodied species, it is likely to cluster with other smaller-bodied species and its absence therefore does not have any major effect on the regression line of the graph and the estimation of the mass of N. magnus.

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