Mesosperchus, Ponomarenko, 1977

Fikáček, Martin, Prokin, Alexander, Angus, Robert B., Pono, Alexander, Marenko, Yue, Yanli, Ren, Dong & Prokop, Jakub, 2012, Revision of Mesozoic fossils of the helophorid lineage of the superfamily Hydrophiloidea (Coleoptera: Polyphaga), Acta Entomologica Musei Nationalis Pragae 52 (1), pp. 89-127 : 123

† ‘ Mesosperchus ’ schultzi Ponomarenko, 1985

( Figs. 101 , 117–118 )

Mesosperchus schultzi Ponomarenko, 1985a: 142 .

Type locality and age. Germany, Bavaria,Solnhofen (current GPS coordinates 48.0°N 11.0°E).Solnhofen Formation, Late Jurassic, Early/Lower Tithonian, 150.8–145.5 mya ( LABANDEIRA 2003).

Material examined. HOLOTYPE: NHMW 1985 /20 (piece and counterpiece).

Taxonomic note. The holotype, which is the only available specimen of this species, is preserved as a three-dimensional impression in a whitish limestone without any fossilized organic remnants, which makes it rather difficult to examine. Unfortunately, except the contiguous procoxae, only dorsal characters are preserved and the precise taxonomic assignment of the species is therefore impossible. The shape of the head and the presence of the large clypeus and distinct frontoclypeal suture resembles some groups of Hydrophilidae , but a study of better preserved specimens would be necessary to confirm this placement as the Hydrophilidae are not known from the Jurassic so far. Hence, we are considering the species as Polyphaga incertae sedis with possible affinity to the Hydrophiloidea for the time being.

Figures

Figs. 94–103. Taxa excluded from the hydrophilid lineage. 94–99 – ‘Mesohelophorus’ mongolicus Ponomarenko, 1986 (94–95 – PIN 3152/4355, holotype, piece and counterpiece; 96, 99 – PIN 3152/4312, piece and counterpiece; 97 – same specimen, detail of head in dorsal view; 99 – head and prosternum of the holotype). 100 – ‘Mesosperchus’ angulatus Ponomarenko, 1985, holotype; 101 – ‘Mesosperchus’ schultzi Ponomarenko, 1985, holotype, piece; 102–103 – ‘Mesosperchus’ notatus Ponomarenko, 1977, holotype (102 – general view; 103 – detail of elytral structure). Scale bars: 0.5 mm.

Figs.113–119.Taxa excluded from the helophorid lineage. 113 – Helo- phoropsis brodiei (Giebel, 1856), holotype; 114 – ‘Mesosperchus’ angulatus Ponomarenko, 1985, holotype; 115 – ‘Mesosperchus’ notatus Ponomarenko, 1977, holotype; 116 – Tychon antiquum (Giebel, 1856), holotype; 117–118 – ‘Mesosperchus’ schultzi Ponomarenko, 1985, holotype, piece and counterpiece; 119 – Zetemenos sexlineatus Bode, 1953, holotype. Scale bars: 1 mm.