On the Staphylinidae of La Gomera ( Canary Islands ) , with descriptions of four new species ( Coleoptera )

The results of a field trip to La Gomera are presented. More than 45 species of Staphylinidae were re­ corded, at least 31 of them either Canarian endemics or island endemics of La Gomera. Four species, all of them presumably island endemics, are described and distinguished from related taxa: Micropeplus gomerensis sp. n., Leptobium gomerense sp. в., Oligota stefaniae sp. n., mdAlevonota sollemnis sp. n. Their sexual characters and further distinguishing characters are figured.

m aterial collected by Wollaston (but discovered in the Sharp and Cameron collection) from Tenerife and Fuerteventura and on further material from La Gomera (Puthz, 1966). However, this easily recognized species inhabits the Laurisilva (which is absent on Fuerte ventura) and has, since its description, exclusively been collected on La Gomera, where it is ra th e r common. The evidence, therefore, suggests that the records from Tenerife and Fuerteventura are based on mislabelled specimens and that S. endemus is in fact an island endemic of L a Gomera, D uring an excursion to L a Gomera in December 1998, more than 4300 specimens o f more than 45 species o f Staphylinidae were collected. As several of the species have only rarely been recorded -some o f them were described only recently -the results are listed below. In addition, the m aterial yielded four species new to science, which are here hypothesized to represent endemics o f L a Gomera and w hich raise the number of island endem ics to at least 19 (S. endemus not included).

Material and acknowledgements
M aterial from the following institutions and private collections was examined:

DEI
Deutsches Entomologisches Institut (L. Z e r c h e ) cAss author's private collection cOro Private collection P. Oromi, La Laguna cWun Private collection P, Wunderle, Monchengladbach I am indebted to the colleagues indicated above for the loan of material. In addition, I would like to express my sincere thanks to Michael Schülke, Berlin, for a critical review of the manuscript, to Ing. Angel Fernández, Parque Nacional de Garajonay, La Gomera, for issuing a collecting permit, and to Dr. Pedro Oromí, La Laguna, for his kind assistance in contacting the authorities.

Measurements
The measurements in the descriptions are indicated in mm and abbreviated as follows: HW; maximal head width including eyes HL: head length from front margin of clypeus to neck PW: maximal width of pronotum PL: length of pronotum along median line EW: maximal width of elytra (in Micropeplus at anterior margin) EL: length of elytra from apex of scutellum to elytral hind margin TL: total length from apex of mandibles to hind margin of tergum Vm.    , 1998b). M ost o f the new records are from the same area, but one 9 was also taken in the west o f the Parque N acional de Garajonay, w hich reveals a wider distribution in the Gomeran Laurisilva. In contrast to S. aeneotinctus aeneotinctus WOLLASTON, which was common especially in Fayal-Brezal associations, S. exspoliatus seems to be confined to m ature laurel woods (Tab. 1). A sim ilar, though less pronounced preference was observed for S. endemus PUTHZ. ASSING, V.: On the Staphylinidae ofLa Gomera

Habrocerus canariensis Assing & WUNDERLE:
This Canarian endemic is much more common on La Gom era than on other islands of the Canarian islands and preferably occurs in m ature laurel woods rather than in Fayal-Brezal associations (see also A ssing & WUN DERLE, 1995). Tw o specimens collected on 24.XII, were teneral; previously, an immature specimen had been found in July (ASSING & Wunderle, 1996). These observations suggest that either the species is not monovoltine or its life-cycle is not distinctly synchronized.
A theta laeta (Wollaston): This species, which according to the literature also occurs on Tenerife an d E l H ierro (Hernández et al., 1994), was rather common in m ature laurel woods, but only rarely found in Fayal-Brezal and other w'oodland associations.   Pronotum somewhat resem bling that of M. staphylinoides, but anterior m argin more deeply concave and w ith m ore pronounced anterior angles, and median cells narrow er (Figs la , b). Elytra highly distinctive, very short, transverse (see ratios EL/PL and EL/EW), and fused at suture; humeral costa distinctly bent (in M. staphylinoides ± straight), so that the lateral pints of the elytra are clearly risible in dorsal view, especially in posterior half; as in M. staphylinoides w ith two discal costae, but the areas between sutural and first and between first and second costa narrower, and with only one and two rows of large punctures, respectively (in M staphylinoides with two and three rows) (Figs la, b). Hind wings completely reduced (in M. staphylinoides often fully develo ped). Tibiae w ith cf secondary' sexual characters sim ilar to M. staphylinoides (Fig. le).

Descriptions o f new species
Abdomen in o' w ith m edian carina of tergm n VII in lateral view form ing a right or slightly obtuse angle ( in M staphylinoides this angle is acute). cf; aedeagus of sim ilar morphology as in M. staphylinoides, in ventral view w ith slightly wider and shorter apex (Figs lc , d). A s sin g , V,: On the Staphylinidae ofLa Gomera C o m p arative notes: From all its W estern Palaearctic congeners, this species is readily distinguished by external morphology' alone, especially the short and fused elytra and the curved hum eral costa. D istrib u tio n : Previously, the genus had been recorded from the Canaiy Islands only once.

FRANZ (1995)
lists a Micropeplvs scheerpeltzi Nohel as an endemic species for E l Hierro, but apparently this species has never been described. The reduced hind wings as well as the short and fused elytra suggest that M gomerensis is endemic to La Gomera, where it was collected both in the Laurisilva o f E l Cedro and in Fayal-Brezal near La Laguna A lta and La Laguna Grande. O ne d* collected in April was teneral.
Leptobium gomerense sp, n.  Larger tlian its only Gomeran congener, L. debilipenne (WOLLASTON) and of different coloration: whole body uniformly reddish brown, abdomen at most only very indistinctly darkened, not bico loured. (In L. debilipenne, the forebody is ± yellowish brown, the appendages are testaceous, and the abdomen is clearly bicoloured, with segments HI -VI dark brown to black, the apex yellowish).
Head of sim ilar shape as in L. debilipeme, also w ith very small eyes, w hich are 0.28 -0.3 5x the length o f postgenae in lateral view, but punctation somewhat denser-surface usually without, but occasionally (1 FT) with shallow microsculpture.
Pronotum as in L. debilipenne, but punctation on average finer and slightly denser; surface usually without, rarely (1PT) w ith shallow microsculpture. E ly tra as in L. debilipenne very short (see ration EL/PL); hind wings completely reduced; abdomen more densely punctured than in L. debilipenne. <?: sternum VIH deeply incised, but less so than i n i . debilipenne (Figs 2c, d); aedeagus in relation to body size smaller, apically broader and less acute; subapical ventral sclerite of different shape (Figs 2a, b).
C o m parativ e notes: Even without exam ining the types there is no doubt that i . debilipenne is here interpreted correctly, as Wollaston (1865) states that that species is "so remarkable for its clear rufo-testaceous hue (the four basal segments of the abdomen being alone black)"; for further distinguishing characters see diagnosis. From all other Canarian species o f Leptobium (see HERNÁNDEZ et al. 1994;CoiFFAIT, 1982), both L. gomerense and L. debilipenne differ in their respective coloration, the distinctly sm aller eyes and shorter elytra, as well as in the morphology o f the aedeagus.
Distribution and bionomics: Like L. debilipenne, L. gomerense is obviously endemic to La Gomera, not only because tliis conspicuous species has not yet been discovered on any other island of tire Canarian archipelago, but especially because of its reduced eyes and wings, which make a wider distribution seem highly unlikely. In contrast toL. debilipenne, which according to WOLLA STON (1865) and my own observations occurs in woodland (Laurisilva, Fayal-Brezal), L. gome rense was collected under stones in open grassland. The locality at Teselinde was only a few hun dred metres from a degraded Laurisilva (same altitude), where L. debilipenne was rather common.

Figs 3a, d
Holotype o': E. Islas Canarias; 3, La Gomera; 900 -1000m; E l Cedro; E rm itá N. S. de Lourdes; Laurisilva, 24.XII.1998, V. A ssing (cAss). Paratypes: Id*, 19, same data as holotype (cAss); lo ', 12, E. Islas Canarias;15, La Gomera;900 -1000m;El Cedro;SW Ermitá N, S, de Lourdes;ca. 1050m, 27.XII.19982cfcf, E.;Isl. Can., Gomera, Bosque del Cedro, Weg zur Ermita, 900m, 17.7.1995, leg. Zerche (DEI, cAss). <f: sternum VIII w ith m ore convex h in d m argin and less transverse than in 0. pseudohirtus (Figs 3d, e), aedeagus of sim ilar morphology, but ventral process of median lobe less evenly arched (lateral view), apically narrow er and less acute (ventral view), ventral crista smaller, internal structures o f slightly different shape (Figs 3a, b). In O. hirtus Williams, the median lobe is larger, the ventral process is m uch longer and more straight (lateral view), and the internal structures are of different shape (Fig. 3c). As SING, V,; On the Staphylinidae of La Gomera D eriv atio nom inis: I dedicate th is species to Stefanie Busch, who contributed to the discovery o f this and other new species described here by spending a considerable stretch of tim e, even Christm as Eve, in the cloudy Laurisilva rather than on a sunny beach and by coping w ith an apartm ent that in the course of certain entomological activities w as both somewhat rearranged and populated by num erous non-staphylinid arthropods. Colour o f body uniform ly reddish brow n w ith the legs, the basal and the apical antennom eres slightly lighter. Head of ovoid shape; surface w ith distinct ± isodiametric microsculpture and w ith fine punctation; eyes very small, composed ofca. 20 ommatidia, and with pigmentation; antennae short and stout, antennom eres IV -X distinctly transverse and increasing in width (Fig. 4g); mouthparts (Figs 4d -f, h) as in A rufotestacea (Kraatz). Pronotum slightly wider than head w ith maximal w idth near anterior angles; surface almost m at due to distinct m icroreticulation, punctation fine, rather dense, and barely visible; median line with shallow and narrow longitudinal impression, w hich is obsolete in the anterior 1/4 to 1/3 o f pronotum; pubescence on either side of median line rather dense, depressed, and directed transversely laterad. A s s in g , V.: O n the Staphylinidae of La Gomera E lytra short (see ratio EL/PL), fused at suture; punctation fine and rather dense; pubescence between suture and sides rather dense, depressed, and almost transverse; hind w ings com pletely reduced. Fig. 4: Alevonota sollenmis sp. n (a -1) and A. rufotestacea (K r a a t z ) (m -q): median lobe of aedeagus in lateral (a) and in ventral view (a, o); apical lobe of paramere (b); spermatheca (c, p); labrum (d, n); labium (e, m); mentum (f); antenna (g); right mandible (h); S tergum VIH (i); hind margin of ¥ sternum VIII (j, q); hind margin of & tergum V E (k); hind margin of tf sternum V E (1).
Legs of sim ilar relative length as in A. rufotestacea.
Abdomen long and of subparallel shape, only indistinctly widened posteriorly; terga III -V w ith moderately deep transverse impressions; punctation fine and rather dense.
<f: tergum VIII with convex hind m argin, pubescence posteriorly rather long, thin and not very dense (Fig. 4k); sternum VIII posteriorly obtusely pointed, pubescence near hind margin thin and of variable length (Fig, 41); aedeagus w ith shape and internal structures o f median lobe and w ith morphology and chaetotaxy of apical lobes of param eres highly sim ilar to A. rufotestacea (Figs 4a, b). $; tergum VIII sim ilar to < ? (Fig. 4i); sternum VIII posteriorly with median concavity, hind m argin with row of short and stout modified setae and with micropubescence (Fig. 4j); sper m atheca (Fig. 4c) of sim ilar morphology as in A , rufotestacea. D erivatio nom inis: This remarkable species was discovered on Christmas Eve. C om parative notes and systematics: The new species without doubt belongs to Alevonota T h o m s o n . With the type species of that genus, A. rufotestacea (KRAATZ), it shares the following characters: the shape and size of tire body, the morphology of the antenna, ligula, maxillary and labial palpi (Figs 4e, m), the shape and chaetotaxy of the labrum (Figs 4d, n), the microsculpture of the forebody, tire general pubescence pattern of pronotum and elytra, the longitudinal impression along the pronotal midline, the shape of the abdomen, the chaetotaxy of the ¥ sternum VIII (Figs 4j, q) and of the apical lobe of the paramere, the sltape and the internal structures of the median lobe (Figs 4a, o), and the general morphology of the spermatheca (Figs 4c, p). A. sollemnis differs fromri. rufotestacea especially in tire coloration, the much smaller eyes, the more oblong head, the more distinct pronotal microsculpture, the denser and more transverse pubescence of the pronotum. the shorter and fused elytra, the absence of hind wings, the more distinctly concave hind margin and tire stouter and shorter modified setae of the ? sternum VIII, and the slightly different shape and smaller size of the spennatlieca. From other microphthalmous and anoplUlialmous Aleochannae occurring in tlie Canary Islands, which are currently attributed to Apteranopsis Je a n n e l and other genera,.-! sollemnis is readily distinguished particularly by the less reduced, pigmented eyes, which are composed ofca. 20 ommatidia and by the fused elytra. A preliminary examination of some of these species revealed that it is quite possible that they, too, may belong to Alevonota, but this question will have to be dealt with on a broader scale (A s s i n g & WuNDERLE, in prep.). D istrib u tio n : The reduction o f the eyes, the short and fused elytra, and the absence of hind wings suggest that A. sollemnis is endemic to La Gomera, where it was sifted from Laurus litter in the Laurisilva of E l Cedro.