Araliaephyllum formosum (HEER) GREGUŠ et J. KVAČEK 2015

Greguš, Josef & Kvaček, Jiří, 2015, Revision Of Cenomanian Flora From The Maletín Sandstone, Acta Musei Nationalis Pragae Series B 71 (3 - 4), pp. 315-364 : 330-331

Araliaephyllum formosum (HEER) GREGUŠ et J. KVAČEK comb. nov.

Pl. 14, Fig. 3; Pl. 15, Fig. 1–4

1869 Aralia formosa HEER , p. 18, pl. 8, fig. 3.

1889 Araliphyllum formosum (HEER) VELENOVSKÝ , p. 50, 54, 59, fig. 116.

1999 Dicotylophyllum formosum (HEER) KNOBLOCH , p. 42, pl. 16, fig. 12, 13, 14, 18.

H o l o t y p e: GPIT/PL_728, Pl. 14, Fig. 3; Heer 1869,

p. 18, pl. 8, fig. 3.

T y p e l o c a l i t y: Maletín.

S t r a t i g r a p h y: Peruc-Korycany Formation, Cenomanian, Upper Cretaceous.

M a t e r i a l s t u d i e d: GBA_1, 107, 108, 109, 124, 125, 126; MMT(M)/G_350, 423; MMT(Z)/G_349; MZM/ 118_49; NHMW_9, 25.

Oc c u r r e n c e i n t h e C z e c h r e p u b l i c: Bohdánkov, Lipenec, Na Rovinách u Kounova, Otruby, Rudka, Peruc, Praha-Hloubětín, Praha-Vidoule, Trubějov, Velké Opatovice.

R e m a r k s o n n o m e n c l a t u r e: Heer (1869), when describing this new species as Aralia formosa , mentioned only one specimen in the protologue, which is therefore understood to be the holotype .

E m e n d e d d i a g n o s i s. Trilobately palmate leaves with lanceolate lobes, entire-margined in basal parts, dentate to serrate in apical parts with acute or rounded apices. Leaf base cuneate; venation actinodromous.

D e s c r i p t i o n. The holotype ( GPIT / PL _728, Pl. 14, Fig. 3) described by Heer (1869, p. 18, pl. 8, fig. 3) is an impression of a trilobate leaf, 68 mm long and 88 mm wide. Individual lobes (measured in incision: medial 42× 20 mm, lateral 50× 19 mm) divided by two deep (up to 2/3 of leaf lamina) sinusoidal incisions. Lobes entire-margined in basal parts, serrate in apical parts. Lobes lanceolate, widest at their midpoints. Base of leaf lamina cuneate to acute, with 15 mm long petiole. Apical parts of lobes rounded to slightly acute. Three relatively wide primary veins run out run out at an angle of 35° radially from one point near base terminating in apical parts at an angle of 35° radially from one point near base terminating in apical parts of lobes. Second and third order venation is not observed .

Other material from Maletín consists of 13 pieces of leaf impressions, morphologically similar to the holotype. Leaves are always trilobate with lobes separated by deep sinusoidal incisions. Second and higher order venation is not always observed. Specimen no. GBA _107 (Pl. 15, Fig. 1a) shows elliptical to obovate lobes (measured in incisions: medial 70× 26 mm, lateral 57× 22 mm); lobes are widest in their upper half. Specimen no. MMT ( M)/ G _350 (Pl. 15, Fig. 4) shows entire-margined lobes, obtusely serrated in the terminal part. The basal part of the leaf impression ( NHMW _25, Pl. 15, Fig. 2) is acute, with 18 mm long petiole. Specimen no. MMT ( M) G _423 (Pl. 15, Fig. 3) has a cuneate base .

Apical parts of leaf impressions of this species are rounded to shortly acute. Three primary veins run out at an angle of 35° radially from one point near base. These relatively pronounced veins terminate in apical parts of the lobes.

Specimen no. GBA_107 (Pl. 15, Fig. 1b) shows well preserved venation. Secondary veins run out at a 40° angle from each primary vein. They occasionally dichotomise in the marginal part of the leaf. Intersecondary veins are present between secondary veins. Close to the midvein, there is venation rather percurrent which is gradually changing to reticulate pattern near the margin of the leaf lamina.

D i s c u s s i o n. Araliaephyllum formosum differs from Araliaephyllum kowalewskianum (SAPORTA et MARION) GREGUŠ et J. KVAČEK comb. nov. ( Saporta 1879, 1881) from Vyšehořovice (Cenomanian) in having serrate apical parts of lobes and always trilobate leaves.

Very close to A. formosum stands “ Aralia ” triloba VELENOVSKÝ from the Cenomanian of Praha-Malá Chuchle and Vyšehořovice ( Velenovský 1882). It has morphologically very similar leaves, but it differs in having individual lobes completely, very delicately serrate (not only in terminal parts, as it is characteristic for A. formosum ). A. formosum is similar to “ Aralia ” decurrens VELENOVSKÝ from Vyšehořovice ( Velenovský 1884), but A. formosum differs in having broader and shorter lobes. Lobes of A. decurrens are typically narrow in their bases. A. formosum differs from “ Aralia ” minor VELENOVSKÝ from Vyšehořovice ( Velenovský 1882) in having more delicate and regular serration of lobes. Lateral lobes of A. minor are up to 50% smaller than the medial lobes, and the leaf is not cuneate in its basal part. Leaves of A. minor can be even pentalobate. A. formosum differs from A. elegans VELENOVSKÝ from Vyšehořovice ( Velenovský 1884) in having serrate, trilobate leaves with cuneate base, with third order venation. A. formosum differs remarkably from A. daphnophyllum VELENOVSKÝ , A. propinqua VELENOVSKÝ and A. transitiva VELENOVSKÝ from Vyšehořovice and Kounice localities ( Velenovský 1882), which have simple, entire-margined, and rounded to ovate and lanceolate leaves. These leaves, classified as Aralia by Velenovský (1882) and later by Frič and Bayer (1903), do not belong by their morphology to Araliaephyllum .