Lasius productus Wilson 1955

Seifert, Bernhard, 2020, A taxonomic revision of the Palaearctic members of the subgenus Lasius s. str. (Hymenoptera, Formicidae), Soil Organisms 92 (1), pp. 15-86 : 78

4.4.54 Lasius productus Wilson 1955

Lasius productus Wilson 1955 [description]

The extremely elongated appendages of this species are outstanding among the Holarctic Lasius of any subgenus. Wilson (1955) presented the following measurements for the holotype worker from Mt. Imano / Shikoku, leg. Okamoto: CL 1.17 mm, CW 1.04 mm and SL 1.17 mm. A scatterplot of SL and CW places the holotype within the cluster of the 16 conspecific specimens studied here and completely outside the clusters of any Palaearctic species. The holotype data translate into CS 1105 µm, CL/CW 900 1.176 and SL/ CS900 1.164.

All material examined. A total of 6 nest samples with 16 workers were subject to NUMOBAT investigation. These originated from Japan. For details see supplementary information SI1.

Geographic range. Distributed over the Japanese islands Tsushima, Kyushu, Shikoku and Honshu. Three altitudinal records range from 50 to 1000 m.

Biology. Connected to broad-leafed deciduous forest. Nesting in rotten wood on ground or in dead parts of tree trunks. Nuptial flight in August and September.

Diagnosis ( Tab. 11 , Figs. 103 –104; key; image in www. antWeb.org with specimen identifier CASENT0903217):

Large (CS 1050 µm). Head and scape length indices outstandingly large (CL/CW 900 1.139, SL/CS 900 1.169). Postocular distance rather small and eye rather large (PoOc/CL 900 0.235, EYE/CS 900 0.248). Torulo-clypeal distance large (dClAn 900 5.65). Terminal segment of maxillary palp outstandingly long (MP6/CS 900 0.293). Pubescence on clypeus moderately dense (sqPDCL 900 4.35); frontal pubescence of medium length (PLF 900 28.8). Scape densely covered with decumbent pubescence hairs. Gular setae rather long, only slightly shorter than pronotal setae (GuHL/CS 900 0.117, PnHL/CS 900 0.134); setae numbers rather low (nOcc 900 9.8, nGen 900 3.2, nGu 900 3.1, nSc 900 10.2, nHT 900 6.7, nSt 900 1.9). Coloration: varying from concolorous medium brown to bicolored with contrasting reddish brown mesosoma and dark brown head and gaster.

Comments: Lasius productus is unmistakable due to the extremely long scape and maxillary palp segments.

Figures

Figs. 103 and 104: Lasius productus; paratype, CASENT0903217, photo W.Ericson