Arthmius vividus ( Motschulsky, 1855 )

Chandler, Donald S., 2013, Further Notes on the New World Pselaphinae (Coleoptera: Staphylinidae) Described by Victor Motschulsky, The Coleopterists Bulletin 67 (3), pp. 321-327 : 323

Arthmius vividus ( Motschulsky, 1855)

Batrisus vividus Motschulsky 1855: 14 . Type locality: Obispo, Panama. Specimens examined: 3, // Batrisus vividus m Obispo/ [gold circle]/ SYNTYPES Batrisus vividus Motschulsky //: 1 male with abdomen missing; 1 female in good condition, 1 female incomplete and in parts [ ZIN]. ZMUM with 1 teneral female specimen: // Obispo [green label]/ [green label, cannot decipher writing]/ Batrisus vividus Motsh Panama //.

Batrisus vividus Schaufuss 1874: 282 . C. Schaufuss 1888: 18. New synonymy.

Batrisus (Arthmius) vividus Schaufuss : Raffray 1898: 479.

Arthmius vividus (Schaufuss) : Raffray 1904: 74, 1908: 152, 1911: 57; Park 1942: 232; Blackwelder 1944: 92.

Arthmius vividus (Motschulsky) : Chandler 1992: 348.

Batrisus (Arthmius) coronifer Reitter 1883: 375 . Synonymized by Raffray (1898: 505).

Batrisus rivularis Motschulsky 1855: 14 . Type locality: Obispo, Panama. Specimens examined, 2 males: // Batrisus rivularis m Obispo / [gold circle]/ C. Motschulsky / SYNTYPES Batrisus rivularis Motschulsky ♂♂ // [ZIN]. ZMUM with 4 specimens on two cards, first card, 1 female // [green circle with portion cut off]/ Batrisus rivularis Motsh Panama //; second card, 3 specimens // [irregularly cut green label]//, male left, females center and right. The male is in very good condition. New synonymy.

Batrisus rivularis Motschulsky “ in litt.,” listed under Batrisus vividus: Raffray 1898: 505, 1904: 74 , 1908: 152.

Comments. After providing a brief description of A. vividus, Motschulsky (1855) simply separated this species from B. rivularis by commenting that both were very similar, but that B. vividus was slightly smaller in size. While not helpful, this is a comparative statement separating the two species, and is judged to validate Motschulsky’ s description of B. rivularis . Schaufuss (1874), believing that both of Motschulsky’ s descriptions were invalid due to the briefness of their descriptions, described both species as new and based the names on labeled Motschulsky specimens that he had obtained from the collection of L. J. Reiche. In doing so, Schaufuss (1874: 285) selected and described a specimen as B. rivularis that had two basal spines on the pronotum, which led Raffray (1898: 439) to place this species in the then subgenus Oxarthrius Reitter of Batrisus Aubé. Since Motschulsky sometimes mounted specimens of different species or even genera on his cards with a single identification label below (see syntypes discussed for species above), this may explain Schaufuss’ error in selecting a specimen of Oxarthrius for his description of B. rivularis . Reitter (1883) also believed that Motschulsky’ s names were invalid and that Schaufuss may have had specimens of a different species before him when he discussed B. vividus , and proposed the name Batrisus coronifer based on Motschulsky specimens that were labeled as B. vividus .

Raffray (1898: 505–506) straightened out this mess when he examined specimens that the others had or had not seen, but continued the dismissal of Motschulsky’ s authorship of the two names. He synonymized B. coronifer Reitter with B. vividus Schaufuss and recognized Schaufuss’ description of B. rivularis as a valid description, but also that it was not proposed in the sense of Motschulsky’ s name, which he maintained as invalid. Chandler (1992) recognized Motschulsky’ s authorship of B. vividus (now a member of the genus Arthmius LeConte ), while B. rivularis was maintained as Oxarthrius rivularis (Schaufuss) .

In examining the available syntype series of both species from the ZMUM and ZIN, specimens placed as B. vividus are slightly smaller than B. rivularis as Motschulsky stated, but males are present in the series for both species, and their vertexal modifications and all other features are identical, supporting Raffray’ s conclusion that both species in the sense of Motschulsky are synonyms. The two species names are briefly characterized and differentiated by Motschulsky, so the names are available. Batrisus rivularis Motschulsky is here finally formally placed as a junior synonym of B. vividus Motschusky , and Batrisus vividus Schaufuss is similarly placed as a junior synonym (new synonymies).

Males of this species may be identified by using the key in Park (1942). A male specimen from Madden Forest Preserve in the former Canal Zone (14 km NE of Obispo) has been labeled as favorably compared with the male type of B. rivularis , and a male from Las Cumbres (near Lago en Las Cumbres, 17 km E of Obispo) has been labeled as favorably compared with the male type of B. vividus . Both specimens are currently held in my collection.