Anisodromum schimperi (Lesquereux) Wang & Dilcher, 2018

Wang, Hongshan & Dilcher, David L., 2018, Early Cretaceous angiosperm leaves from the Dakota Formation, Hoisington III locality, Kansas, USA, Palaeontologia Electronica (34 A) 21 (3), pp. 1-49 : 30-32

Anisodromum schimperi (Lesquereux) comb. nov.

Figure 19.3-4

Basionym. “ Persea” schimperi Lesquereux (1892, p. 103, plate 16, figure 5).

Emended specific diagnosis. Lamina margin entire. Primary venation pinnate; primary vein stout, multi-stranded, course straight. Secondary venation festooned brochidodromous; secondary veins moderate relative to primary veins, subopposite to alternate, decurrent, spacing irregular, with one side more closely spaced than the other side; secondary vein curved apically, joining tertiary veins from superadjacent secondary veins to form two series of loops. Tertiary veins moderate relative to secondary veins, predominately percurrent, orthogonal reticulate near primary vein; course irregular, straight or sinuous; primary-tertiary vein angle oblique.

Description. Whole lamina and base symmetrical, lamina elliptic, L / W 1.5, lamina 2.9 cm to 3.1 cm wide and 4.5 cm to 5.5 cm long. Apex obtuse. Base acute normal. Margin entire. Petiole not observed. Primary venation pinnate; primary vein stout, multi-stranded, course straight. Secondary venation festooned brochidodromous; secondary veins moderate relative to primary vein, ca. seven pairs per lamina, subopposite to alternate, decurrent, spacing irregular, with one side more close than the other side; angle of divergence narrow acute to moderate acute (45 ° to 65º), with one side apparently more acute than those of the other side; secondary vein curved apically, joining tertiary veins from superadjacent secondary veins to form two series of loops. Tertiary veins moderate relative to secondary veins, predominately percurrent, orthogonal reticulate near primary vein; angle of origin ( AO); course irregular, straight or sinuous; primary-tertiary vein angle oblique. Veins of higher order not observed.

Number of specimens examined. 2.

Neotype (designated here). UF15706-24633 ( Figure 19.4 ).

Other specimens illustrated. UF 15706-24635 ( Figure 19.3 ).

Remarks. Characters such as entire margin, multi-stranded primary vein, and festooned brochidodromous secondary venation indicate the affinity of this species with Magnoliales , but the uneven secondary vein spacing may indicate these specimens may represent leaflets of a compound leaf.

Lesquereux (1893, p. 103, plate 16, figure 5) described one specimen from a locality in Minnesota, USA and assigned it to the extant genus Persea . In this report, we retain Lesquereux’s species epithet and transfer his specimen to Anisodromum . Because his original specimen is lost and he did not designate a type, we here emend his species diagnosis and designate a specimen from the Hoisington III locality as the neotype.

Figures

FIGURE 19. 1-2, Anisodromum upchurchii sp. nov., UF15706-24576, middle portion of lamina showing strong primary and secondary veins (scale bar equals 1 cm) (1) and enlargement of an area in Figure 19.1 (indicated by arrow) to show percurrent tertiary veins (scale bar equals 2 mm) (2). 3-4, Anisodromum schimperi (Lesquereux) comb. nov., UF15706-24635, leaf showing uneven spacing of secondary veins and reticulate tertiary veins (scale bar equals 5 mm) (3) and; UF15706-24633, leaf showing secondary venation and reticulate tertiary veins (scale bar equals 5 mm) (4).