Cephennomicrus typicus (Scott) Scott, 2008

Jałoszyński, Paweł, 2008, Taxonomic notes on the Cephenniini (Coleoptera, Scydmaenidae): Status of Coatesia Lea, Cephennomicrus Reitter, and Neseuthia Scott, Zootaxa 1696, pp. 25-36 : 30-32

Cephennomicrus typicus (Scott) , comb. n.

Neseuthia typica Scott, 1922: 203 .

Type material. Lectotype (designated here; Figs. 5, 9 ): SEYCHELLES: Mahé: male, mounted on card bearing male symbol and number "117" handwritten in black, " Mahe, '08-9 Seychelles Exp." (typed), "Percy Sladen Trust Exped. Brit.Mus. 1926―246." (typed), " Type " (circular, white with red margin, typed), " Neseuthia typica TYPE. H.Scott [handwritten in black] TYPE [printed, highlighted in blue]", " Figured specimen " (red, printed), " typicus Scott [handwritten in black] Cl. Besuchet dét. [printed] X [handwritten in black] 195 [printed] 7 [handwritten in black]", " NESEUTHIA typica Scott , LECTOTYPE; P. JAŁOSZYŃSKI, 2007" (printed), " CEPHENNOMICRUS typicus (Scott) , det. P. JAŁOSZYŃSKI, 2007" (printed) ( BMNH). Paralectotypes (2 males, 1 female): SEYCHELLES: Mahé: 1 female, mounted on card bearing female symbol and number "104", labels as in lectotype but lacking the red label "Figured specimen"; 1 male mounted on different (newer?) card than previous specimens, " Paratype " (circular, white with yellow margin, typed), "Percy Sladen Trust Exped. Brit. Mus. 1926-246" (typed), " Neseuthia typica H. Scott , Paratype " (printed), " Mahe, 1908-9. Seychelles Exp." (printed), and similar Besuchet's label as that shown in Fig. 9 and found in all specimens; 1 male mounted on the same type of card as the previous specimen, " Paratype " (circular, white with yellow margin, typed), "Ma(y?)e, 1908-09, Seychelles Exp." (handwritten in black, in easily recognizable Besuchet's hand). All paralectotypes with additional labels " NESEUTHIA typica Scott , PARALECTOTYPE; P. JAŁOSZYŃSKI, 2007" (printed), " CEPHENNOMICRUS typicus (Scott) , det. P. JAŁOSZYŃSKI, 2007" (printed) (all specimens in BMNH).

Remarks. Besides the characters given in the diagnosis, all species of Cephennomicrus are extremely small, typically much smaller than 1 mm in length. Very small species can also be found in the Palearctic genera Nanophthalmus and Cephennium , but the body as small as 0.6 mm, not uncommon in Cephennomicrus , makes this genus exceptional within the tribe. The body shape found in this genus is typical for the Cephenniini, with subquadrate pronotum and stout, short elytra, but the constriction between the pronotum and elytra is usually more distinct than in other genera. The antennae show some degree of variability, and since two relatively distinct variants can be found, in future they may be used for defining species groups or subgenera. Antennae in C. perpunctillum , the type species of Cephennomicrus , and in most of other described species, have two terminal antennomeres enlarged, and at first sight the antennal club appears two-segmented. However, closer examination usually reveals that antennomere IX, though clearly smaller than abruptly enlarged X and XI, is still much larger than VII, and can be regarded as belonging to the club. The other variant can be seen in several species, which have more slender antennal club, with antennomeres X and XI enlarged to a lesser extent than those in C. perpunctillum . In such cases (like in C. nomurai (Jałoszyński & Hoshina, 2003)) the club is very indistinctly separated from the funicle, but it still can be regarded as composed of 3 antennomeres. It can be concluded that Cephennomicrus has 3-segmented antennal club, and the extreme variants taken alone do not represent a diagnostic character to define separate taxa at the rank of subgenus or genus. However, the slender variant may co-occur with the longitudinal median groove on the pronotum found in some described and undescribed species from Japan and Taiwan; this combination, when confirmed, may serve as a potential subgeneric diagnostic feature.

The eyes in all species of Cephennomicrus known to the author are very large, strongly protruding laterally from the silhouette of the head, and usually coarsely faceted. This is an interesting character, as miniaturization in the Cephenniini often affects the eyes, which in such cases are usually very small or even entirely missing in minute subterraneous, lightly pigmented species of Nanophthalmus , Cephennium or Etelea . Oriental species of Cephennomicrus are rarely collected by methods based on sifting, but more frequently by flight intercept traps. The large eyes composed of a large number of ommatidia may therefore be important for flight-related activities.

A high degree of variability can be found in the shapes and structures of the aedeagus among the known species of Cephennomicrus ; the type species of the genus and that of Neseuthia can be examples of such a difference ( Figs. 6, 7 ). Again, a more comprehensive study is necessary to subdivide Cephennomicrus using structures of the aedeagus.

Figures

FIGURES 4 – 9. Type specimens of Cephennomicrus perpunctillum Reitter and Neseuthia typica Scott. 4, Holotype male of Cephennomicrus perpunctillum (0.80 mm). 5, Lectotype male of Neseuthia typica (0.97 mm). 6, Aedeagus of the holotype of Cephennomicrus perpunctillum in dorsal view (0.17 mm). 7, Aedeagus of the paralectotype of Neseuthia typica in dorsal view (0.15 mm). 8. Set of original labels on the holotype of Cephennomicrus perpunctillum. 9, Set of original labels on the holotype of Neseuthia typica.