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Janjucetus
Taxonomy
Janjucetus was named by Fitzgerald (2006).
It was assigned to Mammalodontidae by Fitzgerald (2010), Geisler et al. (2011), Marx and Fordyce (2015), Boessenecker and Fordyce (2015), Marx et al. (2016), Fordyce and Marx (2016), Tsai and Kohno (2017), Berta (2017), Fordyce and Marx (2018); and to Janjucetidae by Fitzgerald (2006), Duncan et al. (2025).
It was assigned to Mammalodontidae by Fitzgerald (2010), Geisler et al. (2011), Marx and Fordyce (2015), Boessenecker and Fordyce (2015), Marx et al. (2016), Fordyce and Marx (2016), Tsai and Kohno (2017), Berta (2017), Fordyce and Marx (2018); and to Janjucetidae by Fitzgerald (2006), Duncan et al. (2025).
Species
Species lacking formal opinion data
Synonymy list
| Year | Name and author |
|---|---|
| 2006 | Janjucetus Fitzgerald p. 1 |
| 2010 | Janjucetus Fitzgerald p. 373 figs. Table 1 |
| 2011 | Janjucetus Geisler et al. p. 6 figs. Table 1 |
| 2015 | Janjucetus Boessenecker and Fordyce figs. Table 1 |
| 2015 | Janjucetus Marx and Fordyce figs. Figure 2 |
| 2016 | Janjucetus Fordyce and Marx p. 114 figs. Fig. 4 |
| 2016 | Janjucetus Marx et al. p. 104 |
| 2017 | Janjucetus Berta p. 166 |
| 2017 | Janjucetus Tsai and Kohno |
| 2018 | Janjucetus Fordyce and Marx p. 5 figs. Fig. 4 |
| 2025 | Janjucetus Duncan et al. p. 8 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
G. †Janjucetus Fitzgerald 2006
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†Janjucetus dullardi Duncan et al. 2025
†Janjucetus hunderi Fitzgerald 2006
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| R. J. Duncan et al. 2025 | Janjucetus is a genus of brevirostral toothed mysticetes (condy-
lobasal length ∼490 mm) with proportionally large orbits, robust skulls, and heterodont dentition with relatively large tooth crowns. The genus is diagnosed by the following synapomorphies follow- ing Fitzgerald (2006): (i) maximum anteroposterior diameter of orbit >20% of overall condylobasal length; (ii) two dorsal infra- orbital foramina on the ascending process of the maxilla; and (iii) lateral edges of the nasals converge anteriorly. Furthermore, Janjucetus differs from Mammalodon in having (newly proposed characters based on the work below marked with an ‘*’): (i) a rostrum that is anteroposteriorly longer than the inter- temporal region rather than subequal; (ii) a rostrum tip that is pointed rather than bluntly rounded; (iii) robust, anteriorly expanded premaxillae, which contact one another anteriorly and form an anterior rosette; (iv) more laterally opening orbits and more posteriorly oriented postorbital processes; (v) having an anteroposteriorly foreshortened and mediolaterally broad ascend- ing process of maxilla, which does not reach the posterior extent of the nasal; (vi) having a low sagittal crest and paired parasagittal clefts along the dorsal surface of the parietal; (vii) a posterior end of the ascending process of the premaxilla in line with the anterior half of the supraorbital of the frontal; (viii) a more dorsally rather than laterally oriented nuchal crest; (ix) mandibles with externally concave profiles in dorsal view; (x) an anterior apex of the man- dible that is not medially recurved; (xi) an obliquely truncated rather than squared anterior margin of the tympanic bulla in ven- tral view; (xii) an inner posterior prominence of the tympanic bulla mediolaterally broader than the outer posterior prominence at the widest point of the bulla; (xiii) periotic body and posterior process greatly exceed the posterior margin of the fenestra rotunda*; (xiv) a diagonally oriented anteroexternal sulcus, which extends from the fovea epitubaria to the anterodorsal angle*; (xv) anteroposterior and dorsoventral diameters of anterior process of periotic are subequal to one another rather than two-thirds as long as they are deep (anteroposterior length 75%–80% of dorsoventral depth)*; (xvi) an anterior tubercle present at the midpoint of the anterior keel of the periotic; (xvii) incisors do not share any alveoli; (xviii) a non-polydont mandibular dental formula; and (xix) pos- terior mandibular teeth lack an accessory shelf near the distal base of the crown*. Note that some of the features listed above (i–x, xvii, and xviii) cannot be assessed for all species of Janjucetus. |
Measurements
No measurements are available
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| Source: subo = suborder, o = order | |||||
| Reference: Uhen 2004 | |||||
Age range: Chattian or 27.30000 to 23.04000 Ma
Collections (8 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Chattian | Australia (Victoria) | Cetacea indet. (51393) J. cf (242124) J. dullardi (242125) J. dullardi, J. hunderi (114718) J. hunderi (51394) J. sp. (51383 176278) J. sp., J. dullardi (46166) |