| Pinus latahensis | |
|---|---|
 | |
| P. latahensis needlesSR 87-61-08 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Pinales |
| Family: | Pinaceae |
| Genus: | Pinus |
| Species: | †P. latahensis |
| Binomial name | |
| †Pinus latahensis | |
Pinus latahensis is anextinctspecies ofconifer in thepine familyPinaceae. The species is known fromfossil leaves found in the earlyEocene deposits of northern Washington state, United States, and southern British Columbia, Canada.
Pinus latahensis was first described byEdward W. Berry in 1929 based on acompression fossil recovered from shale outcrops in theRepublic, Washington area.[1] When published the holotype specimen'stype locality at Republic was misidentified as being an extension of the youngerLatah Formation, located around theSpokane region, which was then considered to be ofLate Miocene age.Roland W. Brown identified that the Republic floras is of an older age and not part of the Latah formation in 1937.[2] The Oligocene age was followed byHerman Becker (1961) while discussing the OligoceneRuby Flora of Montana[3] andJack Wolfe (1965) in discussing the Miocene Fingerrock Wash Flora of Nevada.[4]
In a written communicationc. 1958, Brown again revised the age still older, stating fossils found in the area of Mount Elizabeth, northeast of Republic indicated anOligocene age. This age was used by R.L. Parker and J. A. Calkins (1964) on their assessment of the Curlew Quadrangle of Ferry County.[5] Since then the fossil-bearing strata of theKlondike Mountain Formation have beenradiometrically dated, to give a current estimate of theYpresian, the mid stage of the early Eocene,49.4 ± .5 million years ago.[6]
In his 1955 review of conifer fossils found in thePrinceton coal fields ofBritish Columbia,Chester A. Arnold noted the marked similarities between the Klondike Mountain and Allenby Formations and interpreted the shared taxa of the formations to indicated that the Klondike Mountain Formation was of Oligocene age like the Allenby Formation was thought to be at the time.[7] This similarity was also noted and commented on byCharles Miller (1975) who agreed the Republic and Princeton floras were coeval, and of Eocene age.[8]
Both sites represent upland lake systems that were surrounded by a warm temperate ecosystem with nearby volcanism.[9] The highlands likely had amesicupper microthermal tolower mesothermal climate, in which winter temperatures rarely dropped low enough for snow, and which were seasonably equitable.[10] The Okanagan highlands paleoforest surrounding the lakes have been described as precursors to the moderntemperate broadleaf and mixed forests of Eastern North America and Eastern Asia. Based on the fossilbiotas the lakes were higher and cooler then thecoeval coastal forests preserved in thePuget Group andChuckanut Formation of Western Washington, which are described aslowland tropical forest ecosystems. Estimates of thepaleoelevation range between 0.7–1.2 km (0.43–0.75 mi) higher than the coastal forests. This is consistent with the paleoelevation estimates for the lake systems, which range between 1.1–2.9 km (1,100–2,900 m), which is similar to the modern elevation 0.8 km (0.50 mi), but higher.[10]
Estimates of themean annual temperature have been derived fromclimate leaf analysis multivariate program (CLAMP) analysis andleaf margin analysis (LMA) of both the Princeton and Republic paleofloras. The CLAMP results after multiple linear regressions for Republic gave a mean annual temperature of approximately 8.0 °C (46.4 °F), while the LMA gave 9.2 ± 2.0 °C (48.6 ± 3.6 °F). Princetons multiple linear regression CLAMP results gave a slightly lower 5.1 °C (41.2 °F), and the LMA returned a mean annual temperature of 5.1 ± 2.2 °C (41.2 ± 4.0 °F). This is lower than the mean annual temperature estimates given for the coastal Puget Group, which is estimated to have been between 15–18.6 °C (59.0–65.5 °F). The bioclimatic analysis for Republic and Prionceton suggest mean annual precipitation amounts of 115 ± 39 cm (45 ± 15 in) and 114 ± 42 cm (45 ± 17 in) respectively.[10]
In his assessment of theDriftwood Canyon Provincial Park fossils, originating from an unnamed formation in theOotsa Lake Group and northernmost of the Eocene Okanagan highlands lake system, Rolf Ludvigsen identified the compression 5-needle fossils asP. latahensis. At Driftwood creek, it co-occurs with the permineralized speciesPinus driftwoodensis[11]
Thetype description given by Berry was brief, with an image of the holotype fossil printed in conjunction with three other pine species,Pinus macrophylla,Pinus monticolensis, and the dubiousPinus tetrafolia.[1] Specimen USNM P38082 of theSmithsoniansNational Museum of Natural History collection is the designated speciesholotype,[12] though Berry did not list it as such in the type description. Based on the erroneous assumption that the shales of Republic were part of the Latah formation Berry chose the speciesspecific epithetlatahensis.[1]
In 1961, Becker discussed the taxonomy ofP. latahensis in his monograph on the Oligocene Ruby basin flora of Southwestern Montana. Based on the assumption that the Klondike Mountain Formation was of Oligocene age, he placed several Ruby Basin fossils into a revised definition ofP. monticolensis. Becker noted that the nameP. latahensis was chosen to honor a formation of different age and location then the type locality,[3] and so he opted to suggest synonymy ofP. latahensis intoP. monticolensis as a whole plant species definition. He noted thattaxonomic priority would favor the use of the nameP. latahensis overP. monticolensis, as it was the first species described in the 1929 publication, but chose to ignore the rule.[3]
Three years laterJack Wolfe (1964) also briefly discussedP. latahensis this time in reference to Miocene fossils found of the Fingerrock Wash Flora of Southwestern Nevada. Wolfe took a more conservative approach to the fossils, and suggested that all Oligocene to modern fossils that resemble the livingPinus monticola should be considered to belong to that species. As suchP. latahensis, along with four other fossil species were considered by Wolfe as junior synonyms ofP. monticola.[4]
Needles on theP. latahensis type specimen are 1 mm (0.039 in) wide by approximately 9 cm (3.5 in) long, displaying two faces to each of the 5 individual needles. The needle sheath is deciduous, indicating a possible placement within the "hard" pines. The needles found in the Allenby Formation range 7 cm (2.8 in) or more in length growing from dwarf shoots ranging between 2–3 mm (0.079–0.118 in) in diameter by 5–6 mm (0.20–0.24 in) long.[8] In the type description, Berry noted the fossil examined to be very similar to both the livingwhite pine andsugar pines.[1]