Pistosia terminalis ( Baly, 1869 ) Sekerka, 2015

Sekerka, Lukáš, 2015, Wallacea, Pistosia and Neodownesia: three distinct genera and their tribal placement (Coleoptera: Chrysomelidae: Cassidinae), Acta Entomologica Musei Nationalis Pragae 55 (2), pp. 713-743 : 725-726

Pistosia terminalis ( Baly, 1869) comb. nov.

Estigmena terminalis Baly, 1869: 376 (original description); GEMMINGER & HAROLD (1876): 3606 (catalogue);

DONCKIER DE DONCEEL (1899): 559 (catalogue); WEISE (1911a): 40 (catalogue); WEISE (1911b): 58 (catalogue);

GRESSITT (1957): 210 (South Pacific fauna); UHMANN (1958): 161 (catalogue); UHMANN (1964): 437 (catalogue);

STAINES & STAINES (1999): 525 (Balyʼs taxa list).

Type locality. ‘Tondano’ [= Indonesia, North Sulawesi Province, Minahasa Regency, Tondano].

Type material examined. HOLOTYPE: glued, ‘Type | H. T. [w, p, cb, circular label with red frame] || Tind. | 32. [w, hw, cb, circular label referring to Wallaceʼs diaries] || Baly Coll. [w, p, cb] || Estigmena | terminalis | Baly | Tondano [green, hw by Baly, cb] || [barcode] | NHMUK010210042 [w, p, cb]’ ( BMNH).

Differential diagnosis. Pistosia terminalis can be readily distinguished by narrow and elongate body with pronotum distinctly longer than wide and elytra 2.4× as long as wide (1.8× in the other two species). Additionally it has pronotum with a lateral impression on each side but absent in P. maculata and P. testacea .

Distribution. Indonesia: North Sulawesi ( BALY 1869).

Remarks. BALY (1869) placed the species in Estigmena Hope, 1840 without any specific notes besides the description and since then the species was only listed in catalogues. During my stay in BMNH I had opportunity to study the only existing specimen and found that it lacks setigerous pores on the pronotum and scutellar row of punctures which are present in Estigmena . The specimen has partly broken antennae so only two basal antennomeres of the left antenna and four of the right were preserved but still antennomeres III–IV are tubular like those of Pistosia and not submoniliform as in Wallacea and Neodownesia hence I transfer the species to Pistosia .

BALY (1869) stated that the species was collected by A. R. Wallace at ‘Tondano’ but did not specify the number of specimens he had at his disposal. However, quite likely it was described from only a single specimen as Baly indicated just a single length measurement and other parts of the description also do not suggest that he had more than one. This is also supported by WALLACEʼs (1858 –1866) diary where he stated on page 245 (Insects, page 19 according to Wallaceʼs numbering) following: ‘Hispida.. n. s. on leaf near water’ therefore the specimen is considered as holotype by monotypy. Unfortunately the diary is not particularly clear about the exact locality where the specimen was collected. The list starts on page 246 as beetles collected in ‘N.E. Celebes (Menado)’ and Wallace also gave locality ‘Rurukan, 3500 ft. ’ all written in ink, however, in the same column several rows below he additionally handwrote in pencil ‘Panghu, 1500 ft.?’. On the next page with entry about hispine is no mention of any locality except of various elevations mentioned in other entries on that page.

According to WALLACE (1869) Tondano refers to the area around the Lake Tondano in northern Sulawesi and there are two possible places where the specimen was collected. Wallace left Menado on 22 nd June 1859 and the day after settled for a fortnight at the village Rurukan (approx. 01°20.3′S, 124°52.8′E, ca. 1000 m a.s.l.). From here he made various smaller trips including the village of Tondano (approx. 01°17.9′S, 124°54.4′E, ca. 700 m a.s.l.) and nearby waterfalls. Then Wallace crossed the Tondano Lake on a boat and reached Kakas from where he continued to Panghu (nowadays Pangu, approx. 01°05.7′S, 124°48.9′E, ca. 600 m a.s.l.) where he stayed three weeks and then headed back by the same route.According to the report, Rurukan and Panghu fit best as the likely collecting sites, both mentioned in his diary. Other places, such as villages Tondano, Karas, Langowen (nowadays Langoan) Wallace visited only briefly spending his time mostly with meetings, acquiring provisions and sitting out weather conditions which prevented him from collecting. Wallace mentioned seeing nice growths of palms around Rurukan but regarding Panghu he was more specific and stated: ‘The natives brought me daily a few insects obtained at the Sagueir palms.’ The latter palm refers to Arenga pinnata (Wurmb) Merr. an important species in Sulawesi for production of alcoholic beverage called sagueir ( SIEBERT 1999). Therefore it seems quite likely the type of P. terminalis came from Panghu as palm-associated hispines are very seldom collected unless somebody is truly searching for them.As A. pinnata is widely used by the locals it is probable that they collected the hispine among other insects. On the other hand, the other locality is also possible and the specimen might have been collected somewhere between villages of Rurukan and Tondano.