Spinopinnophyllum S. Kumar, T. Su and M.A. Khan, 2024
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publication ID |
https://doi.org/ 10.26879/1273 |
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persistent identifier |
https://treatment.plazi.org/id/1348B90E-1032-723D-C788-BBA3FAC8FEDF |
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treatment provided by |
Felipe |
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scientific name |
Spinopinnophyllum S. Kumar, T. Su and M.A. Khan |
| status |
gen. nov. |
Genus. Spinopinnophyllum S. Kumar, T. Su and M.A. Khan gen. nov.
PFN003225
Type species. Spinopinnophyllum acanthorachis S. Kumar, T. Su, and M. A. Khan sp. nov.
PFN003226
Etymology. “spino” is used to symbolize the presence of the spine and “pinnophyllum” refers to the pinnately compound leaves.
Species. Spinopinnophyllum acanthorachis S. Kumar, T. Su, and M.A. Khan sp. nov.
Diagnosis. Leaf pinnately compound, leaflets attached to stout rachis; prominent pointed spines ( Figure 3 View FIGURE 3 ) or scars of the base of spines ( Figure 4A View FIGURE 4 ) present on the rachis; preserved leaflets narrow emerging straight from one side of the rachis at an acute angle ( Figures 3 View FIGURE 3 , 4 View FIGURE 4 ); thick and prominent midvein in each leaflet; mid-vein paralleled by prominent secondary lateral veins, oblique and transverse cross veins also present on both sides of the secondary lateral vein.
Holotype. SKBUH / PPL /Um/ L/48 ( Figure 3A View FIGURE 3 )
Paratype. SKBUH / PPL / UL28 ( Figure 4A View FIGURE 4 )
Etymology. The specific epithet “acanthorachis ” is used to symbolize the presence of spines on the rachis of palm leaves.
Type locality. Umaria Ryt. village (N 22 ° 46′26”, E 80 ° 32′19”, 490 m a.s.l.) in Dindori district, Madhya Pradesh, central India GoogleMaps .
Description. The fossil specimens preserve the middle portion of the pinnate leaves, both the petiole and apical portion are not observed; length is 9.2–14.4 cm and width is 1.3–6.9 cm; leaflets are observed on one side of the prominent rachis ( Figures 3A View FIGURE 3 ; 4A View FIGURE 4 ); rachis is stout, 14.2 cm in length and 0.8-1.1 cm in breadth, some faint longitudinal fiberlike structures are also seen on the surface of rachis; 6–7 leaflets are preserved one side of the rachis ( Figures 3A View FIGURE 3 ; 4A View FIGURE 4 ), and the leaflets are attached to the rachis by the entire base, leaflets are narrower at the point of attachment, the terminal portion of the leaflets is not preserved; leaflets are 1.1–6.5 cm long, 0.4–1 cm wide, unarmed, plicate, plication induplicate, emerging at a narrow acute angle from the rachis, thick, coriaceous, and the angle of divergence of leaf segments is 30°– 35°; venation is pinnate, decurrent, and each leaflet has a characteristic thick, distinct, midvein, or primary vein (0.4 mm thick) that is strong and uniform ( Figures 3B, C View FIGURE 3 ; 4C View FIGURE 4 ); about 4–7 distinct lateral veins run parallel on each side of the midvein ( Figures 3B View FIGURE 3 ; 4C View FIGURE 4 ) equidistant from each other, 2° veins are 0.1–0.2 mm apart, some lateral veins lack oblique cross-veins; four spines are clearly observed on the rachis, distinct and well-preserved on a stout rachis; spines are 0.2–0.6 mm long and pointed ( Figures 3 View FIGURE 3 A-C; 4D), and present along the margin of the rachis at an angle of ~61–116° ( Figure 3 View FIGURE 3 D-K); In one specimen, four scars of the base of spines are observed on the rachis ( Figure 4A, C View FIGURE 4 ), distinct spines are also well-preserved within some spine bases ( Figure 4C, D View FIGURE 4 ).
Horizon and age. Deccan Intertrappean beds; latest Maastrichtian (Late Cretaceous)-earliest Danian (Early Paleocene), Chron 29R.
Taxonomic Determination of the New Palm
Genus
The above-mentioned diagnostic features, such as a thick coriaceous pinnate leaf, entirely separated pinnae joined to the strong spiny rachis by their entire narrow bases, pinnate venation, a strong prominent primary vein, and numerous parallel secondaries on either side of the primary vein indicate that our Deccan fossil specimens belong to parts of pinnately leaved palms, especially spiny pinnate palms (family Arecaceae ). Given their fragmentary nature and lack of cuticular information, it is not possible to assign them to a particular modern tribe or genus in Arecaceae . This is because such induplicate types of pinnate leaves are found in a large number of palms, e.g., Areca L., Bentinckia Berry ex Roxb. , Cocos L. (Arecoideae), Calamus L., Plectocomia Martius and Blume ( Calamoideae ), and Phoenix L. (Coryphoideae) (Tomlinson, 1990). In addition, Read and Hickey (1972) have pointed out that numerous similarities in the form and external macromorphological features of palm leaves make it difficult to assign fossil palm leaves to modern palm genera based only on external gross morphology. They also have suggested that no attempt should be made to place fossil palm fragments in modern palm genera unless unquestionably identifiable to them. They provided a key for assigning fragmentary true palm leaves to six fossil genera. They described unarmed palm leaf segments under the fossil genus Amesoneuron , with armed leaf segments on one side under Bactrites , a costapalmate palm leaf with a prominent costa under Sabalites , a palmate leaf segment without any costa under Palmacites , a pinnately compound leaf with pinnae reduplicate on the adaxial surface and without any spines under Phoenicites and a pinnately compound leaf with induplicate pinnae on the adaxial surface, but with lowermost pinnae on the rachis spine-like (like modern genus Phoenix ), under the fossil genus Phoenix . Thus, in being different from Read and Hickey’s fossil genera, especially the pinnately compound fossil leaf genera Phoenicites and Phoenix , we propose a new fossil genus, Spinopinnophyllum S. Kumar, T. Su, and M. A. Khan gen. nov. for the fossil spiny pinnate palm leaf specimens described here.
| PPL |
Agricultural Development and Advisory Service |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.