Trechoides fasciatus Motschulsky, 1856

Schmidt, Joachim & Faille, Arnaud, 2015, Confirmation of occurrence of Trechus Clairville, 1806 in the Baltic amber forests, with description of a flightless edaphic species, and remarks on Trechoides Motschulsky, 1856 (Coleoptera: Carabidae: Trechini), Zootaxa 4028 (4), pp. 539-550 : 540-541

Remarks on Trechoides fasciatus Motschulsky, 1856

In 1855, the Russian entomologist Victor Ivanovitsch Motschulsky visited Danzig, and studied both the extensive collections of Baltic amber inclusions of Georg Carl Berendt (*1790 – †1850) and Anton Menge (*1808–†1880). Based on specimens from the Menge collection (but not from the Berendt collection as erroneously stated by Schmidt 2015) Motschulsky (1856) described 15 species of fossil Coleoptera including four monotypic genera of ground beetles, one potentially representing Trechini . However, the original description of this species is comprised of only a few lines and contains no information that allows for an assessment of the systematic position of the fossil:

“ Trechoides fasciatus Motsch. , forme de Trechus , mais à élytres distinctement tronquées et offrant de longs poils sur les parties latérales de la tête, du corselet et des élytres; ces dernières présentant une bande de teinte foncée sur leur milieu. Long. ½ lign.” ( Motschulsky 1856).

From viewpoint of morphology, remarkable is the apparently small body size of the fossil species (~ 1.6 mm).

Unfortunately, most parts of the amber collection of Anton Menge were lost during the destruction of Danzig during the Word War II. However, in 1944, parts of this and of the equally important amber collection of Otto Helm (*1826–†1902) were packed in wooden crates and transferred to Thuringia, Germany, where much later, fragments were made accessible in the Museum der Natur, Gotha (for a comprehensive analysis of the history of these collections see Krummbiegel & Krummbiegel 2008, Martens 2008). In a provisional listing of the higher level taxa preserved as inclusions in the remains of the Helm & Menge collections, Weitschat (2008) indeed mentioned an unspecified number of representatives of Carabidae , but not any type specimens of species of Coleoptera . However, in a revised but hitherto unpublished version of this list, Weitschat registered no additional ground beetle inclusions (C. Hoffeins 2015, in litt.). Based on a preliminary analysis of the whole inclusion material of these collections, Krummbiegel & Krummbiegel (2008) concluded that only two type specimens of the Menge collection remained preserved. It is thus very probable that most if not all of the Carabidae material, including the type of Trechoides fasciatus as well as the types of the many other taxa of Coleoptera described by Motschulsky (1856) from Baltic amber, are lost. Consequently, the true identity of Trechoides fasciatus remains completely unclear. Truncated elytra and lateral setae on the body are not features of Trechini , and the small size might suggest that Trechoides belongs to another Carabidae tribe, e.g. Zuphiini or Anillini.

The remains of the Helm & Menge collections are now deposited in the Westpreußisches Landesmuseum Münster (Krummbiegel & Krummbiegel 2008, Martens 2008).