Waltonirrisor tendringensis gen. nov. sp n.; Pristineanis, gen. nov. sp n.; Septencoracias simillimus sp, nov. (1 Viewer)

[Fred Ruhe]

Gerald Mayr & Andrew C. Kitchene, 2024

The Picocoraciades (hoopoes, rollers, woodpeckers, and allies) from the early Eocene London Clay of Walton‑on‑the‑Naze

PalZ.
doi:10.1007/s12542-024-00687-9.

Abstract: The Picocoraciades (hoopoes, rollers, woodpeckers, and allies) from the early Eocene London Clay of Walton-on-the-Naze - PalZ

We describe upupiform, coraciiform, and possible piciform birds from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). The material includes partial skeletons of a new species of a small upupiform bird, Waltonirrisor tendringensis, gen. et sp. nov., which is the earliest known representative of the Upupiformes. Three very similar species of stem group rollers are assigned to Laputavis robusta, Septencoracias morsensis, and S. simillimus, sp. nov. These species only differ in minor features, which raises the possibility that the taxon Sepencoracias Bourdon, 2016 is a junior synonym of Laputavis Dyke, 2001. A smaller stem group roller from Walton-on-the-Naze resembles the North American primobucconid species Primobucco mcgrewi. We also describe two species of a new genus-level taxon, Pristineanis, gen. nov., which shows close affinities to the North American “Neanis” kistneri and may be a stem group representative of the Piciformes. In many aspects of their postcranial osteology, the stem group Coracii from Walton-on-the-Naze, as well as the new taxon Pristineanis, resemble coeval Trogoniformes from this fossil site. Because trogons are the extant sister taxon of the Picocoraciades – the clade including the Upupiformes, Coraciiformes, and Piciformes –, the shared similarities are likely to be plesiomorphic for this latter clade. Early Cenozoic representatives of the Upupiformes and Coraciiformes were much smaller than their extant relatives, which suggests that the Picocoraciades are an avian example of Cope’s Rule that postulates a tendency for size increase in evolutionary lineages over time.

P. S,

The new species of Pristineanis, gen. nov. are:
Pristineanis minor, sp. nov. and Pristineanis major, sp. nov.

Enjoy,

Fred

 

[Fred Ruhe]

Systematic palaeontology

Aves Linnaeus, 1758
Picocoraciades sensu Sangster et al. (2022)
Bucerotes Fürbringer, 1888
Upupiformes (Seebohm, 1890)
Waltonirrisor, gen. nov.

Type species. Waltonirrisor tendringensis, sp. nov.

Differential diagnosis. Differs from Messelirrisor Mayr, 1998 in that the processus flexorius of the humerus is strongly distally protruding; the proximal end of the ulna lacks a marked dorsal embossment at the attachment of ligamentum dorsale cubiti; the tarsometatarsus has a wide incisura intertrochlearis lateralis.

Etymology. The taxon name is derived from the name of the type locality and Irrisor, an old name used for a taxon of wood hoopoes (Phoeniculidae).

Waltonirrisor tendringensis, sp. nov.

Holotype. NMS.Z.2021.40.134 (Fig. 1a; partial right coracoid, distal end of right humerus, partial right radius, right carpometacarpus); collected in 1990 by M. Daniels (original collector’s number WN 90655).

Diagnosis. As for genus.

Etymology. The species epithet refers to the Tendring district in the county of Essex, to which Walton-on-the-Naze belongs.

Type locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian, 54.6‒55 Ma; Collinson et al. 2016).

Referred specimens. NMS.Z.2021.40.135 (Fig. 1f; distal portion of left tarsometatarsus); collected in 1982 by M. Daniels (original collector’s number WN 82401). NMS.Z.2021.40.136 (Fig. 1b; vertebra, distal end of left humerus, phalanx proximalis digiti majoris); collected in 1998 by M. Daniels (original collector’s number WN 98982). NMS.Z.2021.40.137 (Fig. 1c; partial mandible, partial furcula, proximal ends of both ulnae, distal end of right ulna); collected in 1979 by M. Daniels (original collector’s number WN 79240). NMS.Z.2021.40.138 (Fig. 1d; proximal end of right ulna); collected in 1982 by M. Daniels (original collector’s number WN 82396). NMS.Z.2021.40.139 (Fig. 1g; distal portion of left tarsometatarsus); collected in 1994 by M. Daniels (original collector’s number WN 94836B). NMS.Z.2021.40.140 (Fig. 1e; distal end of left tibiotarsus); collected in 1996 by M. Daniels (original collector’s number WN 96968).

Measurements (maximum length, in mm). NMS.Z.2021.40.134: carpometacarpus, 9.4.

Remarks. NMS.Z.2021.40.134 and NMS.Z.2021.40.137 were figured by Mayr (1998: pl. 7). The fossils are of similar size to Messelirrisor grandis, which is the largest messelirrisorid known from Messel (other Messelirrisor species are distinctly smaller; Mayr 2006: tab. 1).

Fred


Fig. 1 Specimens of the upupiform bird Waltonirrisor tendringensis, gen. et sp. nov. from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK) in comparison to crown group Upupiformes. a‒g overview of the fossils (a NMS.Z.2021.40.134, b NMS.Z.2021.40.136, c NMS.Z.2021.40.137, d NMS.Z.2021.40.138, e NMS.Z.2021.40.140, f NMS.Z.2021.40.135, g NMS.Z.2021.40.139). h, i W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.137), rostral portion of mandible in ventral (h) and dorsal (i) view. j‒l W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.137), caudal portion of right mandibular ramus in lateral (j), medial (k), and ventral (l) view. m‒o W. tendringensis gen. et sp. nov. (NMS.Z.2021.40.134), omal extremity of right coracoid in dorsal (m), medial , and ventral (o) view; the arrow denotes an enlarged detail. p Phoeniculus purpureus (SMF 6503), right coracoid in dorsal view. q W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.137), partial furcula. r furcula of Ph. purpureus (SMF 65 03). s, t W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.134), distal end of right humerus in cranial (s) and caudal (t) view. u Messelirrisor sp. from the middle Eocene of Geiseltal (GMH L-9–1969) in cranial view. v Messelirrisor halcyrostris from Messel (SMF-ME 2245), right humerus in cranial view. w Ph. purpureus (SMF 7355), distal end of right humerus in cranial view. x M. halcyrostris (SMF-ME 10987a), distal end of right humerus and proximal end of right ulna. y, z W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.137), proximal end of left ulna in cranial and caudal (z) view. aa, bb Ph. purpureus (SMF 7355), proximal end of left ulna in cranial (aa) and caudal (bb) view. cc W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.137), distal end of
right ulna in ventral view. dd Ph. purpureus (SMF 7355), distal end of right ulna in ventral view. ee, ff W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.134), right carpometacarpus in dorsal (ee) and ventral (ff) view. gg M. halcyrostris from Messel (SMF-ME 10987a), left carpometacarpus in dorsal view. hh, ii Phoeniculus purpureus (SMF 6503), right carpometacarpus in dorsal (hh) and ventral (ii) view. jj W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.140), distal end of right tibiotarsus in cranial view. kk‒mm W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.135), distal end of left tarsometatarsus in dorsal (kk), plantar (ll), and distal (mm) view. nn‒pp W. tendringensis, gen. et sp. nov. (NMS.Z.2021.40.139), distal end of left tarsometatarsus in dorsal (nn), plantar (oo), and distal (pp) view. qq M. grandis (SMF-ME 10833), left tarsometatarsus in dorsal view. rr‒tt, Upupa epops (SMF 19549), distal end of left tarsometatarsus in dorsal (rr), plantar (ss), and distal (tt) view. apf apophysis furculae, cdd condylus dorsalis, cdv condylus ventralis, ctd cotyla dorsalis, ctv cotyla ventralis, epd epicondylus dorsalis, flx processus flexorius, fmb fossa musculi brachialis, icl incisura lateralis, icm incisura medialis, ldc attachment site of ligamentum dorsale cubiti, llc attachment site of ligamentum limitans cubiti, mpr medial projection of extremitas sternalis of coracoid, mps attachment site of musculus pronator superficialis, olc olecranon, pim processus intermetacarpalis, pra processus retroarticularis, prj projection of facies articularis clavicularis, tbc tuberculum ventrale, tsd tuberculum supracondylare dorsale, tsv tuberculum supracondylare ventrale.
The scale bars equal 5 mm

 

[Fred Ruhe]

Coraciiformes Forbes, 1884
Coracii Wetmore and Miller, 1926
cf. Primobucconidae Feduccia and Martin, 1976
Laputavis Dyke, 2001

Taxonomic remarks. The holotype of Laputavis robusta (Dyke 2001a) consists of associated fragmentary bones from Walton-on-the-Naze, including partial coracoids, a partial humerus, and a partial tarsometatarsus (Fig. 2a). The species was initially described as “Laputa robusta” by Dyke (2001a), which was later corrected to Laputavis robusta, because the taxon name Laputavis (sic; Laputa FR.) was preoccupied (Dyke 2001b). In the original description, L. robusta was considered to be an apodiform bird, but this classification was poorly founded (Mayr 2001), and Mayr (2009: 130) noted resemblances to the Coraciiformes. We identified two specimens in the Daniels collection that corroborate coraciiform affinities of L. robusta. These two fossils agree with the Laputavis robusta holotype and differ from the specimens we refer to Septencoracias in the shape of the processus acrocoracoideus of the coracoid, which has a less hookshaped outline and a more medially directed tip (Fig. 2).

Laputavis robusta (Dyke, 2001)

Referred specimens. NMS.Z.2021.40.141 (Fig. 2b; two cervical vertebrae, extremitas omalis of right coracoid, fragmentary proximal portion of right humerus, distal portion of right carpometacarpus); collected in 1986 by M. Daniels (original collector’s number WN 86541A). NMS.Z.2021.40.142 (Fig. 2c;
partial left coracoid, extremitates craniales of both scapulae,
furcula, distal end of right humerus); collected in 1987 by M.
Daniels (original collector’s number WN 87576).

Locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Fred


Fig. 2 Fossils of Laputavis robusta and Septencoracias morsensis from Walton-on-the-Naze. a the holotype of L. robusta (NHMUK A 6206). b L. robusta, referred specimen NMS.Z.2021.40.141. c L. robusta, referred specimen NMS.Z.2021.40.142. d, e comparison of the distal humerus and omal extremity of the coracoid of the L. robusta holotype (d) with a specimen we refer to S. morsensis (e: NMS.Z.2021.40.143); the dotted lines indicate differences in the shape of the processus acrocoracoideus of the coracoid and the dorsal margin of the distal humerus. The arrows in b and c denote enlarged details of the coracoid; the lower arrow in b indicates details of the tuberculate encrustations (possible remnants of toe pads) around a pedal phalanx of NMS.Z.2021.40.141 in two views. for foramen, pac processus acrocoracoideus, tsd tuberculum supracondylare dorsale.
The scale bars equal 5 mm

 

[Fred Ruhe]

Septencoracias Bourdon et al., 2016

Taxonomic remarks. The fossils described in the following closely resemble the holotype of Septencoracias morsensis from the Danish Fur Formation, which was described by Bourdon et al. (2016). Characteristic shared derived features include a medially-bent distal end of the first phalanx of the second toe and lateral bulges on the distal ends of the first and second phalanges of the third toe. The material from Walton-on-the-Naze includes at least two very similar Septencoracias-like species, which can be clearly distinguished in the morphologies of the coracoid, furcula, and carpometacarpus. One of these species differs from S. morsensis in some features, while the assignment of the other species to S. morsensis is largely by default.

Septencoracias morsensis has not been compared with Laputavis robusta by Bourdon et al. (2016), and we note that the S. morsensis holotype cannot be differentiated from the L. robusta holotype, because the coracoid is not preserved in the S. morsensis holotype and the humerus and tarsometatarsus allow only very limited comparisons with the similar-sized fragmentary humerus and tarsometatarsus of the L. robusta holotype. The new fossils from Walton-on-the-Naze that we assign to S. morsensis differ from the Laputavis robusta holotype in that the dorsal margin of the distal humerus is straight rather than distinctly concave (Fig. 2d, e). Given the strong overall similarity of the Laputavis and Septencoracias fossils and the coeval ages and geographical proximity of the Fur Formation (the type locality of S. morsensis) and Walton-on-the-Naze (the type locality of L. robusta), we consider it possible that Septencoracias Bourdon et al., 2016 is a junior synonym of Laputavis Dyke, 2001. However and as detailed above, this hypothesis cannot be substantiated or disproven with the currently available fossil material. Regardless of a possible synonymy of the taxa Septencoracias and Laputavis, the two species from Walton-on-the-Naze that we assign to Septencoracias and describe below are distinguished from the specimens we refer to Laputavis robusta.

Septencoracias morsensis Bourdon et al., 2016

Referred specimens. NMS.Z.2021.40.143 (Fig. 3a; partial skeleton including partial mandibular ramus, partial quadrates, several vertebrae, both coracoids, left scapula, furcula, sternum, proximal and distal ends of right humerus, distal end of left humerus, left ulna, both carpometacarpi, both phalanges proximales digitorum majores, left femur, distal end of right tibiotarsus, incomplete left tarsometatarsus, distal end of right tarsometatarsus, pedal phalanges); collected in 1980 by M. Daniels (original collector’s number WN 80285). NMS.Z.2021.40.144 (Fig. 3b; partial skeleton including both quadrates, several vertebrae, right coracoid, extremitas omalis of left coracoid, right scapula, distal end of right humerus, proximal portion of right ulna, partial left radius, left carpometacarpus, right phalanx proximalis digiti majoris, distal portion of right tibiotarsus); collected in 1987 by M. Daniels (original collector’s number WN 87555). NMS.Z.2021.40.145 (not figured; vertebra, left coracoid, extremitas cranialis of left scapula, fragment of furcula, proximal end of left carpometacarpus); collected in 2002 by M. Daniels (original collector’s number WN 021048B). SMF Av 655 (figured by Mayr 2022b; partial skeleton including large portions of the mandible, the left jugal arch, left quadrate, nine vertebrae or fragments thereof, right carpometacarpus, distal section of right radius, nearly complete right tibiotarsus, distal section of left tibiotarsus, right fibula, fragment of left trochlea metatarsi IV, and most pedal phalanges of the left foot).

Locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Measurements (maximum lengths, in mm). NMS.Z.2021.40.143: right coracoid, 20.1; left coracoid, 19.8; left ulna, 37.8 [37.8]; right carpometacarpus, 18.9; left carpometacarpus, 19.0 [17.6]; left femur, 20.7 [20.5]; tarsometatarsus, length as preserved, 14.0; estimated total length, ~ 15.4 [15.5]. NMS.Z.2021.40.144: right coracoid, 20.0; left carpometacarpus, 17.4. Values in brackets indicate the dimensions of the holotype of Septencoracias morsensis (after Bourdon et al. 2016).

Fred


Fig. 3 Fossils of Septencoracias spp. and undetermined Coracii from Walton-on-the-Naze. a, b specimens referred to Septencoracia morsensis (a: NMS.Z.2021.40.143, b: NMS.Z.2021.40.144). c, d S. simillimus, sp. nov. (c: holotype, NMS.Z.2021.40.146 d: NMS.Z.2021.40.147). e, f Coracii, gen. et sp. indet. (e: NMS.Z.2021.40.150, f: NMS.Z.2021.40.152). pyg pygostyle, ste sternum.
The scale bars equal 5 mm

 

[Fred Ruhe]

Septencoracias simillimus, sp. nov.

Holotype. NMS.Z.2021.40.146 (Fig. 3c; partial skeleton including skull, partial right quadrate, several vertebrae, right coracoid, both scapulae, furcula, sternum, right humerus, left humerus lacking proximal end, right ulna, proximal portion of left ulna, right radius, distal end of left radius, left carpometacarpus, proximal portion of right carpometacarpus, both phalanges proximales digitorum majores, proximal and distal ends of right femur, right tibiotarsus, right tarsometatarsus, several pedal phalanges); collected in 1983 by M. Daniels (original collector’s number WN 83456).

Differential diagnosis. Differs from the Laputavis robusta holotype in that the processus acrocoracoideus of the coracoid has a more strongly hooked outline (Fig. 6b, k).
Distinguished from the holotype of Septencoracias morsensis in that the carpometacarpus has a wider spatium intermetacarpale (Fig. 5ff‒hh); the proximal end of the tarsometatarsus is proportionally narrower (ratio of tarsometatarsus length to proximal width 4.5 versus 3.9 in the S. morsensis holotype). Differs from the newly identified fossils we refer to S. morsensis in that the processus procoracoideus of the coracoid points more towards the extremitas omalis (rather than pointing perpendicular to the longitudinal axis the bone; Figs. 5k, l, 6g, k); the scapi clavicularum of the furcula are less widely spayed and the extremitas omalis does not taper to a point (Fig. 5o‒r); the dorsal margin of the distal end of the humerus has a concave (rather than straight) outline (Fig. 6q, t).
Differs from the species of Primobucco in that the beak is proportionally longer (distinctly longer than the neurocranium,
whereas it is shorter than the neurocranium in Primobucco mcgrewi); the processus postorbitalis is more robust; the first phalanx of the hallux is proportionally longer (longer than all other pedal phalanges, whereas it is of subequal length to the first phalanx of the third toe in P. mcgrewi).
The new species is distinctly smaller than the species of Paracoracias and Eocoracias (humerus length 32.1 mm versus 44.4‒45.7 mm in E. brachyptera and 43.6 mm in P. occidentalis), from which it also differs in that the tibiotarsus is slenderer and proportionally longer (subequal to humerus in length, whereas it is distinctly shorter than the humerus in Eocoracias and Paracoracias).

Type locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Referred specimens. NMS.Z.2021.40.147 (Fig. 3d; partial skeleton including left coracoid, extremitas sternalis of right coracoid, furcula, both scapulae lacking caudal ends, sternum, both humeri, left ulna, right radius, distal portion of left radius, right carpometacarpus, proximal portion of left carpometacarpus, both phalanges proximales digitorum majores); collected in 1982 by M. Daniels (original collector’s number WN 82380). NMS.Z.2021.40.148 (partial skeleton including left coracoid, omal portion of right coracoid in piece of matrix, both scapulae, left humerus, distal end of right humerus, distal portion of left ulna, left radius lacking distal tip, left carpometacarpus, both phalanges proximales digitorum majores); collected in 1990 by M. Daniels (original collector’s number WN 90645). NMS.Z.2021.40.149 (extremitas omalis of left coracoid, extremitates sternales of both coracoids, extremitas cranialis of right scapula, fragments of the furcula, distal end of left humerus); collected in 1991 by M. Daniels (original collector’s number WN 91688).

Measurements (maximum length, in mm). NMS.Z.2021.40.146: right coracoid, 20.2; right humerus, 31.7 [31.6]; right ulna, 37.0 [37.8]; left carpometacarpus, 17.1 [17.6]; right tibiotarsus, length as preserved, 29.8 [30.9]; right tarsometatarsus, 14.6 [15.5]. NMS.Z.2021.40.147: left coracoid, 21.5; left humerus, 33.0; right humerus, 31.0; left ulna, 37.0; left radius, 35.2; right carpometacarpus, 18.4. NMS.Z.2021.40.148: left coracoid, 20.3, left humerus, 32.4, left carpometacarpus, 19.5. Values in brackets indicate the dimensions of the holotype of Septencoracias morsensis (after Bourdon et al. 2016).

Remarks. NMS.Z.2021.40.146 was figured by Mayr (1998: pl. 11) and was assigned to Septencoracias by Mayr (2022a: fig. 10.12e).

Fig. 6 The coracoid (a‒n), distal humerus (o‒w), and rsometatarsus
(x‒ww) of Laputavis and Septencoracias fossils from Walton-on-the-Naze. a‒d extremitas omalis of the left (a, c) and right (b, d) coracoid of the holotype of L. robusta (NHMUK A 6206) in dorsal (a, b) and ventral (c, d) view. e, f, L. robusta (NMS.Z.2021.40.141), extremitas omalis of right coracoid in dorsal (e) and ventral (f) view. g, h left coracoid of Septencoracias morsensis (NMS.Z.2021.40.143) in dorsal (g) and ventral (h) view. i, j right coracoid of S. morsensis (NMS.Z.2021.40.144) in ventral (i) and dorsal (j) view. k, l left coracoid of S. simillimus, sp. nov. (NMS.Z.2021.40.147) in dorsal (k) c, d ventral (l) view. m, n right coracoid of S. simillimus, sp. nov. (holotype, NMS.Z.2021.40.146) in ventral (m) and dorsal view. o, p distal end of the left humerus of the holotype of L. robusta NHMUK A 6206) in cranial (o) and caudal (p) view. q, r distal end of the left (q) and right (r) humerus of S. morsensis (NMS.Z.2021.40.143) in cranial (q) and caudal (r) view. s distal end of the right humerus of S. morsensis (NMS.Z. 021.40.144) in cranial view. t‒v distal end of the left (t) and right (u, v) humerus of S. simillimus, sp. nov. (holotype, NMS.Z.2021.40.146) in cranial (t, u) and caudal (v) view. w distal end of the right humerus of S. simillimus, sp. nov. (NMS.Z.2021.40.147) in caudal view. x‒z partial right tarsometatarsus of the holotype of L. robusta (NHMUK A 6206) in dorsal (x), plantar , and proximal (z) view. aa‒ff S. morsensis (NMS.Z.2021.40.143), partial left (aa‒cc) and distal end of the right tarsometatarsus (dd‒ff) in dorsal (aa, dd), plantar (bb, ee), proximal (cc), and distal (ff) view; the arrow denotes an enlarged detail. gg S. morsensis, reconstructed tarsometatarsus of NMS.Z.2021.40.143 by digitally superimposing the partial left tarsometatarsus and the mirrored distal portion of the right tarsometatarsus. hh left tarsometatarsus (dorsal view) of the holotype of S. morsensis (MGUH.VP 9509) with surrounding matrix digitally removed (surface scan, from Bourdon et al. 2016; published under a Creative Commons Attribution 4.0 International License). ii‒ll S. simillimus, sp. nov. (holotype, NMS.Z.2021.40.146), right tarsometatarsus in dorsal (ii), plantar (jj), proximal (kk), and distal (ll) view. mm‒pp Coracii, gen. et sp. indet. (NMS.Z.021.40.150), right tarsometatarsus in dorsal (mm), plantar (nn), proximal (oo), and distal (pp) view. qq‒tt Coracii, gen. et sp. indet. (NMS.Z.2021.40.152), left tarsometatarsus in dorsal (qq), plantar (rr), proximal (ss), and distal (tt) view. uu, vv Microena goodwini, holotype from Bognor Regis (Sussex, UK; NHMUK A 3685) in dorsal (uu) and plantar (vv) view. ww right tarsometatarsus (dorsal view) of an unidentified stem group representative of the Coracii from the early Eocene of Egem in Belgium (IRSNB Av 191; see Mayr and Smith 2019); the specimen was coated with ammonium chloride. xx, yy pedal phalanges of xx S. morsensis (NMS.Z.2021.40.143) and yy S. simillimus, sp. nov. (holotype, NMS.Z.2021.40.146); the toes are identified by Roman numerals. cid canalis interosseus distalis, fdl hypotarsal canal for tendon of musculus flexor digitorum longus, mfv medial foramen vasculare proximale ntc notch in medial margin of extremitas sternalis, pac processus acrocoracoideus, ppc processus procoracoideus, supracondylare dorsale, ttc tuberositas musculi tibialis cranialis.
The scale bars equal 5 mm

 

[Fred Ruhe]

Coracii, gen. et sp. indet.

Referred specimens. NMS.Z.2021.40.150 (Figs. 3e, 6mm‒ pp; proximal end of right femur, right tarsometatarsus, pedal phalanges); collected in 1983 by M. Daniels (original collector’s number WN 83444). NMS.Z.2021.40.151 (distal end of left humerus); collected in 1980 by M. Daniels (original collector’s number WN 80303A). NMS.Z.2021.40.152 (Fig. 3f, 6qq‒tt; distal end of left tibiotarsus, left tarsometatarsus, some pedal phalanges); collected in 1997 by M. Daniels (original collector’s number WN 97979). NMS.Z.2021.40.153 (various fragmentary bones including extremitates sternales of both coracoids, extremitas sternalis of the furcula, distal end of right humerus, proximal end of left ulna); collected in 1993 by M. Daniels (original collector’s number WN 93808).

Locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Measurements (maximum length, in mm). NMS.Z.2021.40.150: right tarsometatarsus, 14.3. NMS.Z.2021.40.152: left tarsometatarsus, 15.0.

Remarks. These four specimens – which we do not assume to belong to the same species – are too incompletely preserved to be unambiguously assigned to one of the above species, which are very similar in size and morphology. NMS.Z.2021.40.150 possibly belongs to Laputavis robusta, and the tarsometatarsus of the specimen closely resembles that of the L. robusta holotype in size and morphology. The caput femoris of the femur of NMS.Z.2021.40.150 forms a proximal bulge, which is absent in the specimens we refer to Septencoracias and, unless it is a pathological feature, may represent an autapomorphy of Laputavis. The other bones are also likely to belong to one of the species described in the present study, but the preserved elements are not diagnostic enough for an unequivocal referral.

Fred

 

[Fred Ruhe]

?Primobucco Brodkorb, 1970
?Primobucco sp.

Referred specimen. NMS.Z.2021.40.154 (Fig. 7a, d‒g; distal end of left tibiotarsus, left tarsometatarsus, several pedal phalanges); collected in 1981 by M. Daniels (original collector’s number WN 81371).

Tentatively referred specimens. NMS.Z.2021.40.155 (Fig. 7b; partial skeleton including both coracoid, extremitas cranialis of right scapula, sternum, partial right carpometacarpus, distal portion of left carpometacarpus, synsacrum, as well as other unprepared bones in small pieces of matrix); collected in 2002 by M. Daniels (original collector’s number WN 021049). NMS.Z.2021.40.156 (Fig. 7c; partial skeleton including left coracoid, right coracoid lacking extremitas sternalis left scapula, right scapula lacking caudal end, partial furcula, partial sternum, distal portions of both humeri, right ulna, right radius, left radius lacking proximal end, left carpometacarpus, carpal bones and wing phalanges); collected in 1988 by M. Daniels (original collector’s number WN 88586).

Locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Measurements (maximum length, in mm). NMS.Z.2021.40.154: left tarsometatarsus, 13.3 [~ 13.1]. NMS.Z.2021.40.156: left coracoid, 15.7 [14.5‒ ~ 16.5]; right radius, 25.2 [28.9‒33.1]; right ulna, 30.7 [30.8‒34.7]; left carpometacarpus, 14.3 [14.0‒15.8]. Values in brackets the dimensions of Primobucco mcgrewi (after Mayr et al. 2004 and Ksepka and Clarke 2010).

Remarks. The tarsometatarsus NMS.Z.2021.40.154 (Fig. 7d‒g) can be unambiguously referred to the Coracii on the basis of a plantarly open canalis interosseus distalis. The bone is smaller than the tarsometatarsi we refer to Septencoracias, from which it also differs in a larger medial foramen vasculare proximale. NMS.Z.2021.40.154 corresponds in size to the tarsometatarsi of Primobucco mcgrewi and P. perneri, which measure ~ 13.1 and ~ 11.5‒13.1 mm, respectively (Mayr et al. 2004). The medial portion of the trochlea metatarsi IV is broken, so that this trochlea probably looks somewhat narrower than it originally was. The coracoids of the tentatively referred specimens NMS.Z.2021.40.155 and NMS.Z.2021.40.156 (Fig. 7i) closely resemble those of the fossils we refer to Septencoracias (Fig. 7j), but they are distinctly smaller (in NMS.Z.2021.40.156 the length of the bone is 15.7 mm versus 19.8‒20.3 mm in S. morsensis and S. simillimus, sp. nov.). The extremitas sternalis exhibits a distinct medial projection. The furcula also corresponds well to that of Septencoracias. However, the trabecula lateralis of the sternum (Fig. 7c) is narrower than in the fossils we refer to Septencoracias. Unlike in Septencoracias (Fig. 7o), the spina externa does not forms a marked dorsal bulge (Fig. 7n). The distal end of the humerus bears a small but welldefined tuberculum supracondylare dorsale (Fig. 7p). Apart from being smaller, the carpometacarpus corresponds well to the carpometacarpus of the fossils we refer to Septencoracias;
the bone agrees with the carpometacarpus of P. mcgrewi in its
length (see measurements above), whereas the arpometacarpi
of P. frugilegus and P. perneri are larger (~ 15.0‒ ~ 17.1 mm in
P. perneri and 18.7 mm in P. frugilegus [Mayr et al. 2004]). The os carpi radiale (Fig. 7l, m) is narrower than the corresponding ossicle of extant Coracii (Fig. 7k) and lacks a sulcus for the tendon of musculus extensor longus alulae, the presence of which was identified as an apomorphy of the Picocoraciades by Mayr (2014). This sulcus is present in Primobucco pecimens from Messel (Mayr 2014), which may challenge an assignment of NMS.Z.2021.40.156 to Primobucco and the Coracii.

Fred

 

[Fred Ruhe]

?Piciformes (Meyer and Wolf, 1810)

Pristineanis, gen. nov.

Type species. Pristineanis minor, sp. nov.

Included species. Pristineanis kistneri (Feduccia, 1973).

Diagnosis. Characterised by a scapula with a long acromion; coracoid with long and slender processus procoracoideus; hypotarsus with two canals (for tendons of musculus flexor digitorum longus and musculus flexor hallucis longus); ramen vasculare distale very large; trochlea metatarsi IV forming a plantarly directed, wing-like flange.

Differential diagnosis. Differs from Neanis Brodkorb, 1965 that the coracoid has a slenderer shaft and a less concave crista articularis sternalis; the distal humerus has a welldefined tuberculum supracondylare dorsale and a more protruding processus flexorius.
Distinguished from the zygodactyl Psittacopedidae in that the tarsometatarsus has a crista medianoplantaris. Differs from the early Oligocene putative piciform Picavus Mayr and Gregorová, 2012 and the early Oligocene Eocuculus Chandler, 1999 in that the foramen vasculare distale of the tarsometatarsus is much larger.

Etymology. The taxon name is derived from pristinus (Lat.),
former, and Neanis, in reference to the fact that the North
American species we assign to this taxon was before known
as Neanis kistneri.
Taxonomic remarks. The tarsometatarsus of Pristineanis
closely resembles that of “Neanis” kistneri from the early Eocene Green River Formation. This species was described as a possible piciform bird by Feduccia (1973), who considered it to be related to Neanis schucherti (Fig. 8c, e), another fossil species from the Green River Formation described by Shufeldt (1913), which is the type species of the taxon Neanis. The holotype of “N.” kistneri is a badly crushed partial skeleton, but a second, more complete and better preserved specimen was reported by Weidig (2010), who likened the species to the piciform Galbulae. This new specimen shows “N.” kistneri to be distinguished from N. schucherti in a proportionally more elongate humerus, and here we assign the former species to the new taxon Pristineanis, as P. kistneri.
Pristineanis minor, sp. nov
Holotype. NMS.Z.2021.40.157 (Fig. 8a; partial skeleton including both coracoids, cranial portions of both scapulae, caudal portion of ?right scapula, partial furcula, fragmentary cranial portion of sternum, distal end of right humerus, fragmentary distal portion of left humerus, distal portion of right ulna, distal portion of left tibiotarsus, both tarsometatarsi, several pedal phalanges); collected in 1984 by M. Daniels (original collector’s number WN 84482B).

Differential diagnosis. Differs from Pristineanis (“Neanis”) kistneri (Feduccia, 1973) in being slightly larger (tarsometatarsus length 12.2‒12.3 mm versus 10.6‒11.6 mm [Weidig 2010]). The new species is distinctly larger than Neanis schucherti Shufeldt, 1913 (length of coracoid 10.8 mm versus 15.6 mm [Feduccia 1976]).

Etymology. The species epithet refers to the fact that this is the smaller of the two Pristineanis species occurring at Walton-on-the-Naze.

Type locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Measurements (maximum length, in mm). Right coracoid,
15.6; left tarsometatarsus, 12.3; right tarsometatarsus, 12.2.

Fred

 

[Fred Ruhe]

Pristineanis major, sp. nov.

Holotype. NMS.Z.2021.40.158 (Fig. 8q‒s; partial left tarsometatarsus and pedal phalanx); collected in 1979 by M. Daniels (original collector’s number WN 79253).

Differential diagnosis. The species differs from P. minor in its notably larger size.

Etymology. The species epithet refers to the fact that this is the larger of the two Pristineanis species occurring at Walton-on-the-Naze.

Type locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Rayner et al. 2009; Aldiss 2012), early Eocene (early Ypresian).

Measurements (in mm). Left tarsometatarsus, length as preserved, 13.4; estimated total length, ~ 14‒15.

Remarks. This specimen is about ten percent larger than the tarsometatarsus of the P. minor holotype. Even though there are some sexually dimorphic extant bird species that show similar size differences, such a pronounced sexual dimorphism in size would be unusual among taxa of the Picocoraciades, and we consider it likely that the specimen belongs to a different species than P. minor. As in the latter species, the tarsometatarsus exhibits a plantarly open canalis interosseus distalis. Other features that can be seen in the specimen likewise correspond to those of P. minor.

Fred