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Icterus turmalis, Molothrus resinosus (1 Viewer)

Peter Kovalik

Well-known member
Slovakia
David W. Steadman and Jessica A. Oswald (2020) New species of troupial (Icterus) and cowbird (Molothrus) from ice-age Peru. The Wilson Journal of Ornithology In-Press.
https://doi.org/10.1676/19-13

Abstract:

In spite of comprising more than 50% of the world's 10,000+ living species of birds, the songbirds (Passeriformes) generally have a poor fossil record. An exception is the Icteridae, with substantial Quaternary fossils at certain sites in North America, South America, and the West Indies. Here we describe 2 new extinct species of icterids from the late Pleistocene Talara Tar Seeps of northwestern Peru. The first is Icterus turmalis, based on 22 fossils (2 skeletal elements); I. turmalis was part of the radiation of “troupial”-type orioles (Icterus icterus s.l.). The second new species, Molothrus resinosus, was a large cowbird based on 15 fossils (4 skeletal elements). Icterus turmalis and Molothrus resinosus are both known thus far only from Talara. They become the second and third extinct species of icterid known from Talara, the other being Euphagus magnirostris Miller 1929, first described from Rancho La Brea, and recorded recently from Talara as well as the Mene de Inciarte Tar Seep in Venezuela. Just as some extant species of icterids often occur today alongside large grazing mammals, the extinct species may have been closely associated with the Pleistocene large mammal community, which collapsed from 15 to 12 thousand years ago.
 
For the description of the non-Passeriform Avisauna from the late Pleistocene Talara Tar Seeps of northwestern Peru see:

Kenneth E. Campbell, jr., 1979
The Non-Passerine Pleistocene Avifauna of the Talara Tar Seeps, Northwestern Peru
Royal Ontario Museum, Life Sciences Contribution 118: 1-203

Free pdf: https://pdfs.semanticscholar.org/97...477.40741151.1597045693-1057835455.1597045693

Lots of new species: Syrigma sanctimartini, Theristicus wetmorei, Eudocimus peruvianus, Nannonetta invisitata, Anas talarae, Anas amotape, Anas sanctaehelenae, Geronogyps reliquus, Gymnogyps howardae, Sarcohamphus fisheri, Miraquila terrestris, Amplibuteo hibardi, Milvago brodkorbi, Viator picis, Belonopterus edmundi, Tringa ameghini, Micropalama chapmani, Nuntius solitarius, Steganopus graui, Thinocorus koepckae, Caprimulgus piurensis

Fred
 
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Lpts pf new s[ecoes: Syrigma sanctimartini, Theristicus wetmorei, Eudocimus peruvianus, Nannonetta invisitata, Anas talarae, Anas amotape, Anas sanctaehelenae, Geronogyps reliquus, Gymnogyps howardae, Sarcohamphus fisheri, Miraquila terrestris, Amplibuteo hibardi, Milvago brodkorbi, Viator picis, Belonopterus edmundi, Tringa ameghini, Micropalama chapmani, Nuntius solitarius, Steganopus graui, Thinocorus koepckae, Caprimulgus piurensis

Micropalama chapmani would be Calidris, Belonopterus edmundi (and Viator?) Vanellus and Miraquila Buteogallus in today's taxonomy. But what about Caprimulgus piurensis? And what on earth is Nuntius solitarius? Some sort of scolopacid, but what kind?
 
Nuntius solitarius:
Remarks
From the specimens on hand it is not possible to determine which genus within the Scolopacidae is most closely related to Nuntius. Nuntius does not bear any close resemblance to any other scolopacid genus except Limnodromus, which it superficially resembles in size and general form. This superficial resemblance of Nuntius to Limnodromus is the reason why L. griseus was chosen to provide a reference point for the osteological characters of this new genus and species presented in the diagnosis. No close taxonomic or evolutionary relationship between Nuntius and Limnodromus is implied, and indeed, the two genera are quite different in numerous critical areas. For example, in the coracoid the shape and orientation of the head, the orientation of the glenoid facet, the shape of the procoracoid, and the size and position of the sternal articular facets are all quite different. These are the types of osteological differences that are to be expected between unrelated genera of different habits, and evolutionary history.
The tarsometatarsus is referred to N. solitarius because it also bears a close superficial resemblance to L. griseus and is of a similar size. It does not resemble Tringa solitaria sufficiently to warrant consideration as an element of T. ameghini. Palnumenius victima L. Miller (1942) was described on the basis of a complete tarsometatarsus from the Upper Pleistocene of San Josecito Cave, Nuevo Leon, Mexico. Palnumenius was described as resembling Numenius more than any other scolopacid genus, and the tarsometatarsus of P. victima is slightly more than twice as large as the tarsometatarsus referred to N. solitarius. Additional characters of the tarsometatarsus referred to N. solitarius that distinguish it from that of P. victima, such as the more proximal position of the internal cotyla relative to the external cotyla, the presence of four hypotarsal ridges instead of three, and a smaller internal trochlea indicate that the two genera are quite different. If the tarsometatarsus referred to N. solitarius should prove to belong to another species, the large size of Palnumenius and its resemblance to Numenius would still indicate that Palnumenius and Nuntius are not congeneric.

In my notes I have both Belonopterus edmundi (and Viator?) in Vanellus.

Miraquila contra Buteogallus: I have following Suárez & Olson, 2009 placed Miraquila terrestris in Buteogallus.

Capromulgus piurensis I don't understand your problem with this. It is just another new spedies described from a complete left coracoid and a right carpometacarpus was referred to it.
Diagnosis
Coracoid agrees with that of Caprimulgus and differs from that of Chordeiles, Nyctidromus Gould, Nyctiphrynus Bonaparte, and Hydropsalis Wagler by having (1) head projecting moderately beyond anterior edge of shaft; (2) brachial tuberosity small. The remaining six genera of South American caprimulgids were unavailable for comparison.
Coracoid differs from that of Caprimulgus longirostris Bonaparte and C. parvulus Gould, the only species of the genus occurring today in southwestern Ecuador and northwestern Peru, and from C. cayennensis Gmelin, the only other small South American species of the genus available, by having (1) head narrow, and anterior projection small (narrow with much larger anterior projection in C. longirostris , wide with much larger anterior projection in C. cayennensis , wide with larger anterior projection in C. parvulus); (2) angle between furcular facet and triosseal canal approximately 125° (approximately 125° in C. longirostris, 135° in C. Cayennensis and 115° in C. parvulus); (3) attachment of M. coracobrachialis of moderate depth, separated anteriorly from attachment of Lig. humero-coracoideum anterius superius by a high ridge (attachment shallow, ridge very small in C. longirostris and C. parvulus; attachment of moderate depth, ridge of moderate size in C. cayennensis); (4) attachment of Lig. humero-coracoideum anterius superius deep, consisting of deep dorsal and moderately deep ventral part separated from each other by high ridge (shallow and of one part in C. longirostris, deep and of one part in C. cayennensis, moderately deep and of one part in C. parvulus); (5) brachial tuberosity undercut by deep concavity (deep in C. longirostris and C. cayennensis, moderate in C. parvulus).

I hope this answers all the questions, but of course, you could also read the paper,

Fred
 
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Back to topic.

Systematic Paleontology

Passeriformes
Icteridae Vigors, 1825
Icterus Brisson, 1760
Icterus turmalis, new species
Holotype. ROM 70056, nearly complete humerus. Paratypes: ROM 70057-70063, 7 partial to nearly complete humeri; ROM 70042-70055, 8 complete and 6 partial coracoids.
Diagnosis. A large-sized species of Icterus distinguished from congeneric species by this combination of osteological characters (Table 3). Humerus: narrow gap between processus supracondylaris
dorsalis and corpus humeri; sulcus humerotricipitalis shallow in anconal aspect; tuberculum supracondylare ventral narrow, angular; sulcus scapulotricipitalis long. Coracoid: tip of facies articularis clavicularis sharp; processus procoracoideus pointed.
Etymology. The name turmalis is derived from the Latin turma, meaning troup or squadron
(Brown 1956:408). We note that the word ‘‘troupial’’ (the common name for members of the Icterus icterus species group) is taken from the French troupiale, referring to gregarious habits (Guralnik 1984:1525). This seems ironic given that troupials mostly occur in pairs or as solitary birds (Hilty 2003:823; Herzog et al. 2016:456). Regardless of social habits in life, Icterus turmalis joined many other species of birds in its final
resting place at Talara.

Molothrus Swainson, 1832
Molothrus resinosus, new species
Holotype. ROM 70031, nearly complete rostrum. Paratypes: ROM 70032-70035, 4 partial to nearly complete rostra; ROM 70021-70029, 5 complete and 4 partial coracoids; ROM 70030, distal humerus
Diagnosis. A medium-large-sized species of Molothrus distinguished from congeneric species by a combination of osteological characters (Table 4). Rostrum: os nasale straight in dorsal aspect; margin of crista tomialis straight in ventral aspect; dorsal surface of fused os nasale and os premaxillare flat. Coracoid: processus acrocoracoideus wide, rounded; processus acrocoracoideus short. Humerus: sulcus supracondylaris dorsalis short; curvature of processus supracondylaris away from corpus humeri narrow; epicondylaris ventralis
narrow in dorso-caudal aspect.
Etymology. Derived from the Latin resina, meaning pitch or gum, the name resinosus means ‘‘full of resin’’ (Brown 1956:653), referring to the Talara fossil site that yielded this extinct species.
Remarks. Being known thus far only from Talara, we do not know whether Molothrus resinosus truly was confined to the Tumbesian region. The discovery of more icterid fossils, whether still entombed at fossil sites or already lying in museum drawers, will evaluate this statement.


Figure 1. The humerus of Icterus in cranial (upper) and caudal (lower) aspects. A. Talara fossil Icterus turmalis holotype, ROM 70056, presumed male based on size. B. Talara fossil Icterus turmalis, ROM 70057, presumed female based on size. C. Modern Icterus icterus ridgwayi (male, Colombia) UF 30896 (old PB catalogue number 20737). D. Modern Icterus croconotus strictifrons (male, Bolivia) LSUMZ 126183. E. Modern Icterus croconotus croconotus (female, Peru) LSUMZ 49015. F. Modern Icterus mesomelas (female, Peru) UF 49200. Based in part on Oswald and Steadman (2015: figure 8).
Scale bars ¼ 10 mm.

Figure 2. The rostrum of extinct and extant cowbirds in dorsal (left column), lateral (center column), and ventral or palatal (right column) aspects. A. Molothrus resinosus, holotype, Talara fossil, ROM 70031, presumed male based on size. B. Molothrus resinosus, paratype, Talara fossil, ROM 70032, presumed male based on size. C. Modern Molothrus bonariensis (male, Peru) LSUMZ 114332. D. Pandanaris convexa fossil (extinct; UF/PB 294), Reddick, Florida, USA. E. Modern Molothrus oryzivorus (female, Venezuela) USNM 344300. Based in part on Oswald and Steadman (2015: figure 7).
Scale bars ¼ 10 mm.

Fred
 

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