The oldest records of Polyxenida (Myriapoda, Diplopoda): new discoveries from the Cretaceous ambers of Lebanon and France Author Duy-Jacquemin, Monique Nguyen Histoire naturelle, Département Systématique et Évolution, Arthropodes, CP 53, 61 rue Buffon, F- 75231 Paris cedex 05 (France) monguyen @ mnhn. fr monguyen@mnhn.fr Author Azar, Dany Lebanese University, Faculty of Science II, Biology Department, BP 26110217 Fanar-Matn (Lebanon) and Department, Saint-Joseph University, Campus of Sciences and Technology, Mar Roukos (Mkalles), BP 11 - 1514 Beirut (Lebanon) azar @ mnhn. fr azar@mnhn.fr text Geodiversitas 2004 26 4 631 641 journal article 10.5281/zenodo.4665318 1638-9395 4665318 Libanoxenus hammanaensis n. sp. ( Figs 3 ; 4 ) TYPE MATERIAL . — Holotype : adult specimen number 633, Azar collection, provisionally deposited in the MNHN . ETYMOLOGY. — After Hammana, the type locality. TYPE LOCALITY AND TYPE HORIZON . — Mdeirij / Hammana locality, Caza of Baabda , Mouhafazit Jabal Loubnan , Central Lebanon ; Early Cretaceous, Valanginian-Hauterivian to lower Aptian (135- 125 million years). The amber piece is mounted on a microscope slide in Canada balsam medium . DIAGNOSIS. — As for genus. DESCRIPTION Adult ( Figs 3 ; 4 A-J) The trunk of the holotype is open over all its length along the axis of symmetry, hence the tergites are not seen entirely. Measurements. Body length = 2.50 mm ; penicil length = 0.30 mm ; head trichomes length = 0.10 mm ; total length = 2.90 mm . Head. Eight ocelli ( Fig. 4A ). Left antenna with eight articles ( Fig. 4A ). Length to diameter ratio of the sixth antennal article = 1.80. Only the end of one sensillum basiconicum is visible on articles VI and VII ( Fig. 4B ); some setiform sensilla are seen on article III, V, VI and VII; right antenna with four articles, the article V is broken. Labrum with numerous small setae ( Fig. 4C ). Outer right palp of gnathochilarium with 12 or 13 sensilla ( Fig. 4D ); it is more than twice as long as the diameter of the middle palp. FIG. 3. — Libanoxenus hammanaensis n. gen., n. sp. , holotype adult body length: 2.90 mm (633), Azar collection, dorsal view. Trunk. The tergal trichomes (seen only on the lateral part of tergites), are short ( Fig. 4E, F ); the longer lateral trichomes of tergite reach 120 to 130 µm while in the middle of the tergite the trichomes measure 50 to 53 µm . They seem to be arranged in two rows: one anterior row with trichomes directed anteriad and one posterior row with trichomes directed caudal ( Fig. 4F ). One clearly visible seta on tarsus II ( Fig. 4G, I ), nude setae ( Fig. 4H ) observed on other article (coxa, trochanter, prefemur, femur and tibia). Telotarsus with clearly visible poste- rior lamellate process longer than claw ( Fig. 4G ). Dorsal face of telson with an anterior row including three to four visible barbate trichomes. Telson is not of Polyxenus and Propolyxenus type (latter with trichomes ended by multiple hooks: Fig. 4K ); trichomes of caudal penicil with three or four aligned hooks ( Fig. 4J ). French amber