FNZ 48 - Scaphidiinae (Insecta: Coleoptera: Staphylinidae) - Introduction and systematics
Löbl, I; Leschen, RAB 2003. Scaphidiinae (Insecta: Coleoptera: Staphylinidae). Fauna of New Zealand 48, 94 pages.
(
ISSN 0111-5383 (print),
;
no.
48.
ISBN 0-478-09353-5 (print),
).
Published 18 Nov 2003
ZooBank: http://zoobank.org/References/FDA38B33-D656-46CB-9406-CA03D26DC811
Introduction
Scaphidiinae presently contains approximately 1400 described species worldwide (Löbl 1997) but many areas require detail study, including the Australasian region. Species diversity is highest in tropical regions, and diminishes towards higher latitudes and tends to be low in higher altitudes. Before this study the endemic New Zealand fauna consisted of eight described species, with 10 species listed by Hudson (1934). The first scaphidiine described from New Zealand was Scaphisoma scutellare Redtenbacher (1867) followed by seven species treated by Broun (1880, 1881, 1886, and 1914) including one species described by Pascoe (1876) that was placed into synonymy by Reitter (1880) and one of Broun's species of Scaphisoma that was later transferred to Leiodidae (Klimaszewski et al . 1996, see Newton 1998). To date, no additional species have been described from the country, although Kuschel (1990) reported seven from Lynfield, Auckland (including natural history information) and Klimaszewski et al . (1996) listed a total of 15 species. As indicated by Klimaszewski et al . (1996), the generic concepts of New Zealand scaphidiines required revision as some species were placed in wrong genera. As is the case with many south temperate Coleoptera, many species described over 100 years ago were placed into existing European genera based solely on similarity, and the basic body form of scaphisomatines (see frontispiece) would not help coleopterists of that time to place taxa. A Eurocentric view of the taxonomic world, coupled with the poorly known limits of some of the scaphisomatine genera, lead to paraphyletic taxa and dubious generic placement of some of the New Zealand species. In this paper we revise the New Zealand species, comment on generic limits, and provide a key to 23 species. Biological information is also summarised for each species.
Systematics of Scaphidiinae
The subfamily Scaphidiinae is a member of the Oxytelinae group of Staphylinidae (Lawrence & Newton 1982), which includes Apateticinae, Osoriinae, Oxytelinae, Piestinae, and Trigonurinae. Unlike most members of the oxyteline group, and the majority of Staphylinidae, scaphidiines do not have the typical flexible staphylinoid body form, but are box-like and highly convex, with the elytra covering most of the abdomen. When seen on fungus-covered logs, the species appear as if they are shiny black pearls that are often fast-running, these features make them easily recognised as scaphidiines.
Based on larval characters, Kasule (1966) was the first to recognise Scaphidiinae as a subfamily of Staphylinidae, despite their long taxonomic history as separate families. It has been a slow process for coleopterists to accept the firm placement of Scaphidiinae within staphylinids, and many works published after Kasule's (1966) paper treat scaphidiines as a separate family (see review in Leschen & Löbl 1995), despite numerous adult characters that support the correct familial placement (Lawrence & Newton 1982; Newton & Thayer 1992).
Scaphidiinae is unequivocally monophyletic based on many adult characters (Leschen & Löbl 1995; Hansen 1997a), including the 5-segmented antennal club, pronotum with a high-volume, and sternites III and VII longer than the others (see Thayer 2003 for a more complete list of characters). Larvae have a unique crenulated labral margin (Newton 1991).
Although the direct sister relationships are uncertain within the oxyteline group, Scaphidiinae appear to be most similar to Apateticinae (Leschen & Löbl 1995), and share at least two characters: abdomen strongly tapering toward the apex, and elongate elytra covering tergites 1 and 2. The phylogenetic study by Hansen (1997a) based on larval and adult characters showed a polyphyletic oxyteline group, and reinstated the subfamily Scaphidiinae as a family - Scaphidiinae (-idae) is sister taxon to the remaining Staphylinidae sensu stricto, and these together are the sister taxon to Scydmaenidae. Another study by Beutel & Molenda (1997) also showed a paraphyletic oxyteline group, but with a largely unresolved Staphylinidae based on characters derived from the larval head. The theoretical study by Ballard et al . (1998) included a preliminary study of molecular and morphological characters that also showed that the oxyteline group (in this case Oxytelus and Cyparium ) were not monophyletic, although the sets of morphological characters and terminal taxa were not sampled exhaustively.
Scaphidiine workers recognise a classification of Scaphidiinae that includes four tribes (Löbl 1997), with Scaphisomatini having the highest number of described species and the most enigmatic phylogenetic relationships. Leschen & Löbl (1995) studied the phylogenetic relationships among the scaphidiine tribes, and the genera contained in Cypariini (Africa, Asia, Neotropical, North America, New Zealand), Scaphiini (Holarctic, Southeast Asia), and Scaphidiini (world wide except New Zealand and Pacific Islands) and demonstrated the monophyly of Scaphisomatini, a tribe that includes five subtribes reflecting higher categories defined by Achard (1924). Also note that the tribes Heteroscaphini and Toxidiini are included within Scaphisomatini and these issues will be adressed in another paper (Leschen & Löbl, in prep.).