Muriwaimanu tuatahi (Ando et al., 2006)

Mayr, Gerald, De Pietri, Vanesa L., Proffitt, James, Blokland, Jacob C., Clarke, Julia A., Love, Leigh, Mannering, Al A., Crouch, Erica M., Reid, Catherine & Scofield, R. Paul, 2025, Multiple exceptionally preserved fossils from the Paleocene Waipara Greensand inform the diversity of the oldest stem group Sphenisciformes and the formation of their diving adaptations, Zoological Journal of the Linnean Society 204 (4) : -

Muriwaimanu tuatahi (Ando et al., 2006) ( Figs. 1–8)

Holotype: OU 12651 (partial skeleton including skull fragments, a partial mandible, vertebrae, ribs, synsacrum, a furcula, right coracoid, extremitas sternalis of left coracoid, cranial portion of right scapula, right humerus, distal end of left humerus, left ulna, left radius, proximal end of right femur).

Type locality and horizon: Waipara Greensand , Waipara River, Canterbury, New Zealand; 43°02'S, 172°32'E; fossil record number M34/f138; collected by Brad Field in the 1980s .

Referred specimens: CM zfa 33 [partial skeleton including neurocranium, vertebrae, ribs, partial scapula, proximal end of right humerus, distal end of left humerus; note that there is a discrepancy in the text and figures of Slack et al. (2006), who on p. 1146 stated that CM zfa 33 includes coracoids and a femur, whereas these elements were only figured for CM zfa 34 by Slack et al. 2006: fig. 1 and are currently not associated with CM zfa 33—we assume that there is an error in the text and that the figure shows the correct association of the elements]. CM zfa 34 (partial skeleton including skull and mandible fragments, left and right coracoids, partial furcula, cranial portion of left scapula, vertebrae, right humerus, left humerus lacking distal end, both radii, left carpometacarpus, caudal portion of synsacrum, pelvis fragments, distal portion of left femur, right tarsometatarsus). CM 2008.145.3 (proximal portion of right humerus). CM 2009.99.1 [partial skeleton including both quadrates (right one has been isolated), numerous vertebrae, both coracoids, both humeri, left ulna, both radii, both carpometacarpi, carpal bones and wing phalanges, left femur, right femur lacking distal portion, right tarsometatarsus, proximal end of left tarsometatarsus, pedal phalanges]. Parts of CM 2009.99.1 were damaged after it was first studied and scanned several years ago, notably the sternum and pelvis (see below). CM 2010.108.3 (partial skeleton including vertebrae, ribs, left coracoid, fragmentary right coracoid, partial right scapula, fragmentary sternum in two halves, partial left and right humeri, left ulna, right ulna lacking distal end, major portions of both radii, synsacrum and fragments of the pelvis, right femur, both tibiotarsi, both tarsometatarsi, pedal phalanges). UC 22077 (fragmentary left coracoid lacking extremitas omalis, right tibiotarsus, distal end of right femur). UC 22078 (skull, partial mandible, right quadrate, vertebrae including pygostyle, right scapula, cranial portion of right scapula,?right omal extremity of furcula, left coracoid, sternal extremity of right coracoid, fragments of sternum, left humerus, left ulna, proximal end of right ulna, fragmented left radius, proximal portion of right radius, both carpometacarpi and phalanges proximales digiti majoris, distal wing phalanges, partial pelvis with synsacrum, proximal portion of left femur, distal portion of right femur, left tibiotarsus, distal portion of right tibiotarsus, left tarsometatarsus lacking proximal end, pedal phalanges, and other fragmentary bones that are poorly exposed).

Locality and horizon: CM zfa 33: site S3; middle to upper Waipara Greensand, near top of exposure; collected by A.A. Mannering in 1997; NZDP 5–7 (possibly zone 7 based on its stratigraphic position and the absence of Isabelidinium cingulatum and Alterbidinium pentaradiatum , presence of Leptodinium pustulatum suggests sample not older than upper NZDP 5). CM zfa 34: site S2; collected by A.A. Mannering in 1997; upper NZDP 5. CM 2009.99.1: site S1; collected by A.A. Mannering on 11.10.2008, more recovered on 2.1.2009; latest Early or Middle Paleocene (Danian or Selandian), NZDP 5– NZDP 6 (about 62.4–59.4 Mya). CM 2008.145.3: site S1; found in situ; collected by L. Love in May 2008; Early or Middle Paleocene (Danian or Selandian). CM 2010.108.3: found in situ on S2 main exposure; collected by L. Love on 1.12.2010; Early or Middle Paleocene (Danian or Selandian). UC 22077: site S1; found in situ approximately 10 m down from top of exposure; collected by L. Love on 8.10.2019; Middle Paleocene (Danian or Selandian), NZDP 7. UC 22078: Laidmore Road; found in situ 1 m above river bed on 11.11.2022 by L. Love; Middle Paleocene (Selandian), NZDP 6 (about 61.3–59.4 Mya), based on the presence of Deflandrea foveolata and I. cingulatum , and absence of A. pentaradiatum .

Measurements (in mm): See Table 1 for the lengths of the major limb bones. Additional measurements: CM zfa 33: left humerus, distal width, 24.7. CM zfa 34: right humerus, proximal width, 34.7; left femur, distal width, 24.8; right tarsometatarsus, distal width, 28.1. CM 2009.99.1: right humerus, proximal end, 33.6, distal end, 25.8; left femur, proximal end, 26.8, distal end, 22.9; left tarsometatarsus, proximal end, 22.9. CM 2010.108.3: right humerus, proximal end, 28.1; right femur, proximal end, 25.6, distal end, 25.7; left tarsometatarsus, proximal end, 24.4, distal end, 25.1. UC 22078: skull, 200; beak, 134; left humerus, proximal end, 33.3, distal end, 24.0; left femur, proximal end, 27.8; left tibiotarsus, distal end, 22.8; left tarsometatarsus, distal end, 28.1.

Remarks: Slack et al. (2006) designated CM zfa 33 and CM zfa 34 as the paratypes of Muriwaimanu tuatahi . CM zfa 34 shows pathological or diagenetically altered morphologies in that the proximal tip of the crista deltopectoralis forms a marked projection that is not present in the left humerus, one of the extremitates omales of the furcula exhibits a well-developed processus acrocoracoideus, which is not present in the other omal extremity, and both coracoids show distinct differences in shape, with the right one having a much wider processus procoracoideus and a shorter extremitas omalis. In both coracoids, the processus acrocoracoideus is less medially directed than in other M. tuatahi specimens.

Waimanutaha gen. nov.

ZooBank LSID: urn:lsid:zoobank.org:act:E5E3C015-750F-4FED-BE7A-AD358DB0C8D4 .

Type species: Waimanutaha kenlovei sp. nov.

Differential diagnosis: Stem group sphenisciform the size of the extant Megadyptes antipodes , which is distinguished from:

i. Muriwaimanu in: humerus with only weakly distally convex crista bicipitalis; humerus shaft mediolaterally wider; femur proportionally shorter, with ratio femur length to ulna length 1.20 [1.34 in Muriwaimanu tuatahi ( CM 2010.108.3 and CM 2009.99.1)]. Furthermore, the holotype has a longersynsacrumthanthe M.tuatahi specimenCM 2010.108.3, even though the tibiotarsus is shorter ( Table 1).

ii. Sequiwaimanu in: humerus with proportionally narrower shaft; carpometacarpus with proportionally shorter os metacarpale alulare; in addition, the atlas of the referred specimen UC 22079 has a craniocaudally shorter arcus atlantis than S. rosieae and the processus spinosus of the axis of UC 22079 is less dorsally projected.

iii. Kupoupou in: ratio femur length to ulna length 1.20 (1.37 in K. stilwelli ); humerus with dorsoventrally wider shaft.

iv. Petradyptes in: humerus with dorsoventrally narrower shaft and less pronounced distally convex crista bicipitalis. v. Kumimanu in: humerus more elongate. vi. Allpost-Paleocenesphenisciformsin:humeruswithnarrower shaft; ulna with processus cotylaris dorsalis;carpometacarpus with proximodistally shorter os metacarpale alulare.

The only skeletal element of the holotype that is directly comparable to the much larger Waimanu manneringi is the tibiotarsus, which shows a similar morphology but is considerably smaller ( Table 1); the tarsometatarsus of the tentatively referred specimen CM 2010.108.1 is distinguished from that of W. manneringi in that the plantar articular surface of the trochlea metatarsi III does not taper proximally.

Etymology: The genus name is derived from Māori and means alongside or beside (taha) Waimanu , and refers to the fact that this species was found in a stratigraphic section of the Waipara Greensand that yielded other ‘ Waimanu -like’ stem group sphenisciforms. The gender of the new taxon is male.

Waimanutaha kenlovei sp. nov. ( Figs. 1, 2, 4‒6, 8, 9, 11, 15)

ZooBank LSID: urn:lsid:zoobank.org:act:439C193A-F3D5-440D-8358-C87EA15B70CA .

Holotype: CM 2018.124 .4 [ Fig. 1B; partial skeleton including mandible, right wing, right femur and right tibiotarsus (both bones erroneously listed as being from the left side by Mayr et al. 2020b), synsacrum, partial pelvis, as well as several thoracic vertebrae and ribs; a smaller second block contains the distal portions of the left ulna and carpometacarpus as well as various other small fragmentary bones; the proximal portion of the left humerus and the left radius are preserved as isolated bones].

Diagnosis: As for genus.

Etymology: The species epithet honours Ken Love (1930– 2019), father of the discoverer L. Love.

Type locality and horizon: Waipara Greensand , Waipara River, Canterbury, New Zealand; from site S1; found on 16.9.2017 by L. Love; latest Early or Middle Paleocene (Danian or Selandian), NZDP5 (about 62.4–61.5 Mya), based on the presence of Vozzhennikovia angulata .

Tentatively referred specimens: CM 2010.108.1 [partial skeleton including vertebrae, partial right scapula, partial furcula, partial? right scapular blade, partial left coracoid (only visible on CT scan), proximal end of left humerus, right humerus, left ulna, proximal end of right ulna, fragments of both radii, proximal end of left femur (only visible on CT scan), proximal ends of both tibiotarsi (right on as an isolated bone), left tarsometatarsus, pedal phalanges]. UC 22079 (partial skeleton on two blocks of matrix, including skull with neurocranium on a different block than upper beak, vertebrae, left coracoid, extremitas omalis of furcula, partial sternum, right humerus, right ulna, right radius lacking distal end, right os carpi radiale).

Locality and horizon: CM 2010.108.1: Waipara Greensand , Waipara River, Canterbury, New Zealand; found about 10 km away from the main area of sites 1–3,near main Waiparaconus seam approximately 3m above river; collected by L.Love on 28.4.2009; late Early or Middle Paleocene (Danian or Selandian) , NZDP5 – NZDP6 (about 62.4–59.6 Mya) . UC 22079 : site S2, found on 16.10.2021 by L. Love; early Late Paleocene (Thanetian), NZDP7 , Waipawa Organofacies (c. 58 Mya), see Crouch et al. (2024) .

Measurements (in mm): SeeTable 1 for the lengths of the major limb bones. Additional measurements: CM 2018.124.4: mandible, ∼ 210; right humerus, proximal end, 31.9; left humerus, proximal end, 30.8; femur, proximal end, 24.9, distal end, 23.1; tibiotarsus, distal end, 20.6. UC 22079: skull, ∼ 185; beak, 135; right humerus, distal end, 25.7. CM 2010.108.1: left humerus, proximal width, 32.7; right humerus, distal width, 25.0; left tarsometatarsus, proximal width, 23.0, distal width, 25.2.

Remarks: The holotype ( CM 2018.124.4) was tentatively referred to Muriwaimanu tuatahi byMayr et al. (2020b), who then noted the different limb proportions to the latter species. The specimen preserves the only articulated wing known from a stem group sphenisciform from the Waipara Greensand, which was described by Mayr et al. (2020b).

Our assignment of CM 2010.108.1 and UC 22079 to Waimanutaha kenlovei is tentative, because there is little overlap in the bones preserved in these specimens and the holotype and most of the diagnostic features of Wt. kenlovei are not visible in the fossils. This referral is mainly based on the similar sizes of the major limb bones of the specimens ( Table 1) and the fact that the humerus has a somewhat wider shaft than in M. tuatahi . CM 2010.108.1 also differs from M. tuatahi in that the atlas is mediolaterally narrower, and UC 22079 is distinguished from M. tuatahi in that the os carpi radiale lacks a sulcus for the tendon of m. ulnometacarpalis ventralis. Furthermore, UC 22079 comes from a younger stratigraphic section than the holotype and CM 2010.108.1.

Archaeodyptes gen. nov.

ZooBank LSID: urn:lsid:zoobank.org:act:BAAF9A30-2218-420A-AB42-FEBB16966735 .

Type species: Archaeodyptes waitahaorum sp. nov.

Differential diagnosis: Stem group sphenisciform the size of the extant Megadyptes antipodes , which is distinguished from:

i. Muriwaimanu in:pygostyle with rounded caudal tip (pointed tip in Muriwaimanu ); proximal portion of radius more strongly caudally inflected; ulna stouter, with ratio length of bone to proximal width being 3.3 (3.7 in M. tuatahi, CM 2009.99.1); humerus with crista bicipitalis not forming a marked distal convexity; only narrow ridge between the incisura capitis and the sulcus transversus; distinct, ridge-like insertion area of m. coracobrachialis caudalis along proximoventral portion of caudal surface of humerus shaft ( Fig. 2D); distally prominent convex protrusion of distal margin of sulcus scapulotricipitalis ( Fig. 2K); tarsometatarsus with distinct fossa metatarsi I. ii. Waimanutaha in: proximal portion of radius more strongly caudally inflected; tuberculum dorsale of humerus shorter (reaching distally only slightly beyond the level of the crus dorsale fossae, whereas it reaches to the level of the crista bicipitalis in Waimanutaha ), crista bicipitalis not forming a marked distal convexity; distally prominent convex protrusion of distal margin of sulcus scapulotricipitalis; ratio femur length to ulna length 1.30–1.33 (1.20 in Waimanutaha ). iii. Sequiwaimanu in: humerus with distally prominent convex protrusion of distal margin of sulcus scapulotricipitalis; carpometacarpus with proportionally shorter processus alularis. iv. Waimanu in: plantar articular surface of trochlea metatarsi III shorter and not proximally tapering. v. Kupoupou in: tarsometatarsus less abbreviated and dorsal surface without intermetatarsal sulci. vi. Petradyptes in: humerus with dorsoventrally narrower shaft and without markedly convex crista bicipitalis. vii. All post-Paleocene sphenisciforms in: humerus with dorsoventrally much narrower shaft, carpometacarpus with proximodistally shorter os metacarpale alulare.

Etymology: The taxon name is derived from archaios (Gr.): old, and dytes (Gr.): diver (changed to ‘dyptes’ to match the spelling of some extant and fossil penguin taxa). The gender of the new taxon is male.

Archaeodyptes waitahaorum sp.nov.

ZooBank LSID: urn:lsid:zoobank.org:act:E293BE78-8145-4247-B78F-CC6BF7354F37 .

Holotype: CM 2020.46.1 ( Fig. 1D; partial skeleton including completebeakwithdetachedneurocranium, isolatedrightquadrate, vertebrae including pygostyle, partial furcula, left humerus lacking distal end, right humerus, left ulna, right radius, proximal portion of right carpometacarpus, right phalanx proximalis digiti majoris, left half of pelvis, both femora, both tibiotarsi, left tarsometatarsus, distal portion of right tarsometatarsus, pedal phalanges).

Differential diagnosis: As for genus. The new species is smaller than M. tuatahi (see Table 1).

Etymology: The species epithet refers to the Waitaha people, who inhabited the South Island of New Zealand.

Type locality and horizon: Waipara Greensand , Waipara River, Canterbury, New Zealand; from site S1; found in situ approximately 5 m down from top of exposure; collected on 28.10.2019 by L. Love; early Late Paleocene (Thanetian), NZDP 7 (about 59.4 –57.6 Mya) .

Measurements (in mm): See Table 1 for the lengths of the major limb bones. Additional measurements: beak ∼ 134; left humerus, proximal end, 27.8; left femur, proximal end, 22.9, distal end, 21.8; left tibiotarsus, distal end, 18.1; right tarsometatarsus, proximal end, 20.8, distal end, 23.7.

Waiparadyptes gen. nov.

ZooBank LSID: urn:lsid:zoobank.org:act:1784C8E1-8381-482D-A9CA-08BF3E2A2662 .

Type species: Waiparadyptes gracilitarsus sp. nov.

Differential diagnosis: Small stem group sphenisciform that is characterized by a furcula with a well-defined, knob-like apophysis furculae (unlike in Muriwaimanu ); the blade of the scapula does not widen and is equally narrow along the entire length of the bone (unlike in Muriwaimanu , Sequiwaimanu , Kumimanu , and all post-Paleocene sphenisciforms); the tarsometatarsus is much more elongated and narrower than in Muriwaimanu , Archaeodyptes , Waimanutaha , Waimanu , and all other sphenisciforms of which the bone is known, with the ratio of the length of the bone to the minimum mediolateral width of its shaft being 5.8 (4.0 in CM zfa 34, a specimen referred to M. tuatahi ).

Etymology: The taxon name is derived from the name of the type locality and dytes (Gr.): diver (changed to ‘dyptes’ to match the spelling of some extant and fossil penguin taxa). The gender of the new taxon is male.

Waiparadyptes gracilitarsus sp.nov.

ZooBank LSID: urn:lsid:zoobank.org:act:956BDA65-1C17-4CD3-9B42-71E73A11C202 .

Holotype: CM 2013.27.1 ( Fig. 1E; partial skeleton including partial skull and mandibles, vertebrae, right coracoid, right scapula, right humerus lacking proximal end, proximal end of right ulna, partial pelvis, right tarsometatarsus).

Diagnosis: As for genus; the new species is distinctly smaller than the above species of Muriwaimanu , Archaeodyptes , and Waimanutaha (see Table 1).

Etymology: The species epithet is derived from gracilis (Lat.): slender, and tarsus, in reference to the slender tarsometatarsus of the new species.

Type locality and horizon: Waipara Greensand , Waipara River, Canterbury, New Zealand; from site S3, just above a bed containing scattered Waiparaconus remains (between NZ Fossil Record Numbers M 34/f656 and M34/f657); collected on 31.12.2003 by A.A. Mannering; late Early to earliest Middle Paleocene (Danian), NZDP5 (about 62.4–61.6 Mya) .

Referred specimens: UC 22080 (left humerus lacking proximal end). UC 22094 (proximal end of left tarsometatarsus).

Locality and horizon: UC 22080 : site S1; found in situ, 4 m above river bed, found on 31.1.2022 by L. Love; Early Paleocene (Danian) , NZDP5 (about 62.4–61.4 Mya) . UC 22094 : site S1, found loose on lower slope; collected on 3.10.2020 by L. Love .

Measurements (in mm): SeeTable 1 for the lengths of the major limb bones. Additional measurements: CM 2013.27.1: right humerus, distal end, 17.1; right tarsometatarsus, proximal end, 15.4, distal end, 18.5.

Remarks: The skull of the holotype was figured by Proffitt et al. (2016), who described its brain endocast morphology.

Daniadyptes gen.nov.

ZooBank LSID: urn:lsid:zoobank.org:act:BDE4CF58-4100-4FB6-8259-DB741D925850 .

Type species: Daniadyptes primaevus sp. nov.

Differential diagnosis: Very small stem group sphenisciform that is distinguished from all other sphenisciforms by a proximodistally short tuberculum dorsale, which is reaching distally only to the proximal terminus of the crus dorsale fossae; the humerus shaft is narrower than in Waiparadyptes , the crista bicipitalis does not form a marked distal convexity, the condylus ventralis is globose, cranially prominent, and separated by a notch from the ventral trochlear ridge; the intertrochlear ridge is shorter and does not reach as far ventrally as the ventral ridge; the ventral trochlear ridge is distally projected so that the distal margin of the humerus is very oblique in cranial view; unlike in other sphenisciforms, a dorsal trochlear ridge is hardly developed.

Etymology: The taxon name is derived from the Danian stage the holotype comes from and dytes (Gr.): diver (changed to ‘dyptes’ to match the spelling of some extant and fossil penguin taxa). The gender of the new taxon is male.