Sphenisciformes (Ksepka & Clarke, 2010)

Park, Travis & Fitzgerald, Erich M. G., 2012, A review of Australian fossil penguins (Aves: Sphenisciformes), Memoirs of Museum Victoria 69, pp. 309-325 : 310-314

Australian fossil Sphenisciformes

The record of Sphenisciformes in Australia is less extensive than that of New Zealand, South America and Antarctica, with a chronologically scattered distribution and the majority of fossils being fragmentary. This limited record probably reflects a lack of systematic field exploration, collecting and research, rather than real rarity of fossils. Until now, the majority of fossil penguin discoveries have been fortuitous in nature. Despite this relatively meagre record, penguins are known from ten localities limited to southeast Australia in every geologic epoch from the Eocene onwards ( Figs. 1 and 3 ; Table 1).

Eocene. Six specimens in total have been described from this epoch ( Finlayson, 1938; Glaessner, 1955; Simpson, 1957; Jenkins, 1974), including the partial skeleton (SAM P14157) of an indeterminate form resembling the Antarctic genus Anthropornis ( Jenkins, 1974; Jenkins, 1985) ( Fig. 4 ; Table 2). Found at Blanche Point, South Australia and originally named as Pachydyptes simpsoni , it is the most complete fossil penguin yet discovered in Australia. Other specimens referred to this Anthropornis -like form include a partial right humerus (SAM P14158a) ( Fig. 5 ; subsequently reassigned this material to Sphenisciformes , indeterminate. A third form, intermediate in size between the Palaeeudyptes and Anthropornis forms is known from two bones, one allegedly found at Blanche Point and the other from late Eocene rocks near Browns Creek, Otway Peninsula, Victoria ( Jenkins, 1985; Vickers-Rich, 1991). These two specimens have not been described, and recent efforts by one of us (EMGF) to locate them in the SAM and MV collections have failed.

Oligocene. Only two fossil penguin specimens are known from the Oligocene of Australia. Both of them were derived from the Camelback Member of the Gambier Limestone, which has been correlated to the P21/22 planktonic foram zone (Lower–Upper Oligocene) ( Li et al., 2000). Both specimens, a partial right humerus (SAM P10863) ( Fig. 8 ; Table 2) and a partial left femur (SAM P10870) ( Fig. 9; Table 2), were first noted by Glaessner (1955) and later described by Simpson (1957). Neither of the specimens has been assigned to a genus or species, but they are considered to be separate taxa ( Simpson, 1957).

Early–Middle Miocene. Fossil penguin specimens have been described from the Early–Late Miocene of Australia. A single specimen was found as float on the banks of the Glenelg River at Devil’s Den, Victoria ( Gill, 1959a; Simpson, 1959). The large right humerus (NMV P17167) was named as Anthropodyptes gilli by Simpson (1959) ( Fig. 10 ; Table 2). From the Early Miocene ( Gill, 1959a; Jenkins, 1974; Dickinson et al., 2002), it is the latest surviving giant stem Spheniscid known, although some extinct crown Spheniscid taxa (e.g. Spheniscus megaramphus ) would have been larger than Aptenodytes forsteri (Ksepka & Clarke, 2010; Stucchi, 2003). As yet undescribed material has also been collected from the Lower–Middle Miocene Batesford Limestone at Batesford, near Geelong, Victoria including: a partial right femur (NMV P222904), a partial left femur (NMV P201867), and a partial left coracoid (NMV P231933). A partial left tibiotarsus (NMV P231836) and a partial right femur (NMV P201856) have also been collected from the Middle Miocene Fyansford Clay at the same locality.

Late Miocene–Pliocene. Mio-Pliocene penguins have been described from two localities: Spring Creek, near Minhamite, and Beaumaris, Victoria. Simpson (1965, 1970), described a total of 21 penguin specimens from these localities. From Spring Creek an incomplete left humerus (NMV P26668, holotype of Pseudaptenodytes macraei Simpson, 1970 ) ( Fig. 11; Table 2), and from Beaumaris: a partial left coracoid (NMV P24065) ( Simpson, 1965) ( Fig. 12 ; Table 2); three partial left humeri (NMV P26671, NMV P26676, NMV P27059) ( Fig. 13 ; Table 2); four partial right humeri (NMV P26669, NMV P26677, NMV P27057, NMV P26670) including the holotype of? Pseudaptenodytes minor Simpson, 1970 (NMV P26669) ( Figs. 13 and 14 ; Table 2); four partial carpometacarpi (NMV P27055, NMV P27056, NMV P27058, NMV P26903) ( Figs. 13 and 15 ; Table 2); and eight isolated fragments (registration numbers unspecified by Simpson, 1970). The P. macraei humerus is the larger of the two species, being similar in size to the humerus of a king penguin ( Aptenodytes patagonicus Miller, 1778 ), whereas the? P. minor humerus approaches that of the gentoo penguin ( Pygoscelis papua Forster, 1781 ) in size.? Pseudaptenodytes minor was referred to Sphenisciformes indet. by Ksepka and Ando (2011: 159). The Upper Miocene Port Campbell Limestone at Portland, Victoria, has yielded a nearly complete left humerus (NMV P221273) and a partial left humerus (NMV P232062). One definitively Pliocene specimen is known from Australia, an undescribed partial right femur (NMV P41738) from the Pliocene Jemmys Point Formation at Red Bluff, west of Lake Tyers, Victoria.

Holocene. Van Tets and O’Connor (1983) described penguin remains from a ca. 760 year-old aboriginal midden on Hunter Island, Tasmania and described these as a new genus and species, Tasidyptes hunteri . Other workers ( Fordyce and Jones, 1990; Ksepka and Clarke, 2010) have doubted this identification due to the fragmentary nature of the fossils: the coracoid (ANWC BS2669) ( Table 2) and tarsometatarsus (ANWC BS2668) ( Table 2) are indistinguishable from Eudyptes ; and the four specimens comprising the hypodigm (ANWC BS2667, ANWC BS2668, ANWC BS2669, ANWC BS2670) ( Table 2) come from three different horizons within the midden ( Van Tets and O’Connor, 1983; Fordyce and Jones 1990; Ksepka and Clarke, 2010). Baird (1992) reported little penguin ( Eudyptula minor Forster 1781 ) material from a pitfall assemblage in Amphitheatre Cave, Victoria which has been dated to ca. 4670 ybp ( Table 2). However, this Eudyptula material is unlikely to be from the original pitfall assemblage due its differential preservation ( Baird, 1992: 31–32).

Figures

Figure 1. Chronostratigraphy and correlation of Australian fossil penguin-bearing units, compared with the fossil record of Sphenisciformes on other continents. Note that the vertical ranges of stratigraphic units represent estimates of geologic age maxima and minima for penguin-bearing horizons, not necessarily discrete time-spans of deposition. Geologic timescale is after Gradstein et al. (2004) with updates from Walker and Geissman (2009). See Table 1 for references to ages of Australian units. Ages of African units: Hendey (1981); Roberts et al. (2011); Ksepka and Thomas (2012). Ages of Antarctic units: Dingle and Lavelle (2000); Jadwiszczak (2006); Marenssi et al. (2012). Ages of New Zealand units: White and Waterhouse (1993); Cooper (2004); Slack et al. (2006); Ksepka et al. (2012). Ages of South American units: Devries (1998); Scasso et al. (2001); Celma and Cantalamessa (2007); Achurra et al. (2009); Malumián and Náñez (2011); Uhen et al. (2011).

Figure 3. Fossil sphenisciform localities in Australia. 1 = Devil’s Den; 2 = Portland; 3 = Spring Creek; 4 = Batesford Quarry; 5 = Beaumaris; 6 = Red Bluff; 7 = Hunter Island; 8 = Witton Bluff; 9 = Blanche Point; 10 = Mount Gambier

Figure 4. Pachydyptes simpsoni holotype, SAM P14157: A, right radius in ventral view, left carpometacarpus and left phalanx II-1 in dorsal view; B, head of right humerus in dorsal view; C, left coracoid in dorsal view; D,?twelfth cervical vertebra in ventral view.

Figure 5. Pachydyptes simpsoni paratype, SAM P14158: proximal end of right radius in (A) ventral view and (C) dorsal view; partial right humerus in (B) ventral and (D) dorsal views.

Figure 8. Sphenisciformes indet. partial right humerus, SAM P10863: A, dorsal view; B, ventral view.

Figure 10. Anthropodyptes gilli holotype right humerus,NMV P17167: A, dorsal view; B, ventral view.

Figure 12. Sphenisciformes indet. partial left coracoid, NMV P24065: A, dorsal view; B, ventral view.

Figure 13. Sphenisciformes from the Upper Miocene–Lower Pliocene Black Rock Sandstone, Victoria. A–J and M–P, specimens referred to?Pseudaptenodytes minor: partial left humerus, NMV P 26671, in (A) dorsal and (B) ventral views; partial left humerus, NMV P26676, in (C) dorsal and (D) ventral views; partial right humerus, NMV P26677, in (E) dorsal and (F) ventral views; partial right humerus, NMV P26670, in (G) dorsal and (H) ventral views; partial right humerus, NMV P27057, in (I) dorsal and (J) ventral views; partial right carpometacarpus, NMV P27058, in (M) dorsal and (N) ventral views; partial right carpometacarpus, NMV P26903, in (O) dorsal and (P) ventral views. Sphenisciformes indet. partial left humerus, NMV P27059: K, dorsal view; L, ventral view.

Figure 14.?Pseudaptenodytes minor holotype partial right humerus, NMV P26669: A, dorsal view; B, ventral view.

Figure 15. Specimens referred to Pseudaptenodytes macraei: partial right carpometacarpus, NMV P27055, in (A) dorsal and (B) ventral views; partial left carpometacarpus, NMV P27056, in (C) ventral and (D) dorsal views.