Three new species and new records of African Psammoecus Latreille (Coleoptera, Silvanidae)

In the course of work that followed a revision of African Psammoecus Latreille, 1829, predominantly based on material from the Tervuren Museum (Karner 2012), 237 specimens from several other collections were examined. Since little is known about the distribution of African Psammoecus, the present paper makes the new faunistic data available. The material also contained three new species that are described here.


Introduction
In the course of work that followed a revision of African Psammoecus Latreille, 1829, predominantly based on material from the Tervuren Museum (Karner 2012), 237 specimens from several other collections were examined. Since little is known about the distribution of African Psammoecus, the present paper makes the new faunistic data available. The material also contained three new species that are described here.

Notes on some characters
The shape of the temples shows considerable differences between species. Temples may be well developed and wide, or they may be narrowed very steeply. To provide a measure for the degree of narrowing, the angle between the temple and the longitudinal axis of the head can be used (see Fig. 1). The resulting value is called the 'temple angle', it is given as an angular degree.
The pubescence on head and pronotum is composed of mostly semierect setae; the elytral pubescence consists of strial and interstrial setae. In all African species studied by the author so far, the setae are directed anteriorly on the head and pronotum, and posteriorly on the elytra.
Near the anterior angles of the pronotum, small seta-bearing denticles or groups of denticles are present in all African species, sometimes reduced to minute structures. A posterior denticle near the posterior angle is present in most species. Frequently, also the lateral pronotal margins bear teeth of different size, shape and pattern. Teeth along the lateral pronotal margin -located between anterior and posterior denticles -are numbered in roman numerals, starting anteriorly, and are named 'T I', 'T II', etc. Setae originating from these teeth are more or less damaged in most museum specimens; they are extremely fragile and prone to being damaged during collection of specimens in the fi eld. Even in well conserved material, specimens with undamaged setation (such as shown in Fig. 2A) are rarely observed. While the cleaning of specimens for photography would be desirable from an aesthetic point of view, any attempt to remove dirt, dust particles, etc. was found to severely damage the pubescence even in well softened specimens. For that reason, it was not attempted to clean specimens, even though the aesthetics of photographs was somewhat compromised.

Material and Methods
Measurements were taken as follows: Length: from apical margin of clypeus to apex of elytra Head width: across eyes Head length: from apical margin of clypeus to imaginary line between hind margins of eyes Eye length: from anterior to posterior margin Antennal length: from base of 1 st antennomere to apex of 11 th antennomere Pronotal width: across maximum width, excluding spines Pronotal length: from anterior to posterior margin Elytral width: across maximum joint width Elytral length: along suture including scutellum Relative proportions (lengths) of antennomere are listed from 1 st to 11 th antennomere. Microsculpture was assessed at 80x magnifi cation.
For dissection of genitalia, the method described by Karner (2012) was used. For photography, the isolated aedeagus was placed in a warm drop of Kaiser's glycerol gelatin (Carl Roth GmbH) to enable precise orientation. After study, structures were embedded in dimethylhydantoin formaldehyde resin (Steedman 1958) on a cellulose acetate label and attached to the pin of the respective specimen. KARNER M., New species of African Psammoecus 3 Photographs were taken with a Canon EOS 650D digital camera attached to an Olympus SZX16 stereo microscope and photographs of genitalia were taken with a Canon EOS 650D digital camera attached to an Olympus CH microscope. Images and image layers were processed with Zerene Stacker (Version 1.04 Build T201311272225), Adobe Lightroom 5.3 and GIMP (Version 2.8.0) software.
All label data are given verbatim for type material. The labels are cited beginning with the uppermost one; the respective lines are separated by '|'. Comments on label colors, label shapes, etc. regarding the respective specimen are included in square brackets. Locality and collection data for other material examined are condensed, sorted alphabetically by country.
Specimens from the following collections were studied:

Diagnosis
The following combination of character states is diagnostic for this species: 1 st antennomere 2.1 times as long as 2 nd antennomere; maximum pronotal width near middle; lateral margins of pronotum with distinct, triangular teeth with wide bases, anterior angle of pronotum with distinct denticle; elytral striae narrower than interstices; interstices of lateral elytral striae with very small tubercles; median lobe of aedeagus wide, abruptly narrowed towards apex; parameres distinctly separated from basal piece.

Differential diagnosis
Psammoecus nyakabuyensis sp. nov. resembles P. luchti Karner, 2012 and can be distinguished by its narrower elytral striae; it differs from P. luchti and all other African Psammoecus also by the shape of the male genitalia.

Etymology
The specifi c epithet is derived from the name of the locality where the type material was collected.   -27.2.1985-27.2. [14-27 Feb. 1985]' (MKF). Fig. 2A). Oval, castaneous, total length 3.05 mm. Elytra with transverse, dark brown maculae near middle. Antennomeres 8-10 dark brown, 11 bright testaceous. HEAD (as in Fig. 2B). Eyes large, prominent; temples distinctly narrowed immediately behind eyes, temple angle 65°; head width 0.79 mm, length 0.46 mm. Puncturation on vertex coarse, punctures about 1.25 times as large as an eye facet diameter, contiguous laterally, well separated medially; pubescence composed of short, semierect setae, directed anteriorly; microsculpture absent. Longitudinal impressions on vertex short and shallow, curved outwardly, attaining 1/5 of eyes. Eyes 0.21 mm long, distance of inner margins 0.50 mm. Temples immediately narrowed behind eyes, slightly curved. Antennae  Fig. 2C). Wider than head, lateral margins strongly curved, widest at middle, surface slightly impressed near posterior angles and basis; width 0.90 mm, length 0.64 mm. Anterior angles with small denticles; lateral margins with four wide teeth; T I very small, only slightly larger than anterior denticles, T II about twice as big as T I, T III and T IV of same size, about twice as big as T II; posterior angle with small denticle, located in the middle between T IV and posterior margin. Puncturation and pubescence on pronotal disk as on vertex; punctures more sparse near posterior angles and basis. Microsculpture absent.

PRONOTUM (as in
ELYTRA. Oval, widest at middle, length 2.00 mm, combined width 1.35 mm. Rows of punctures on disc somewhat narrower than interstices; pubescence composed of short semierect setae, strial and interstrial setae of identical length; microsculpture absent. MALE GENITALIA (as in Fig. 2E-G). Parameres wide, moderately narrowed towards apex, bearing numerous long setae near mesal face of basis, shorter setae on ventral edge, and a very long and a short seta at apex; in lateral view strongly narrowed near middle, and widened, somewhat spoon-shaped, towards apex. Median lobe wide, narrowed towards apex in a basally convex, apically concave curve to form a narrow, almost parallel-sided protrusion with blunt tip; S-curved towards apex in lateral view.

Variation
The paratypes vary in body length from 2.92 to 3.30 mm.

Remarks
Even though Psammoecus nyakabuyensis sp. nov. resembles P. luchti in general appearance, the structures of the male genitalia differ very much ( Fig. 3A-B shows the genitalia of P. luchti for comparison). A close relation of these two species is therefore very unlikely.

Diagnosis
The following combination of character states is diagnostic for this species: lateral margins of pronotum with very small teeth; antennomeres slender; 1 st antennomere 3 times as long as 2 nd ; microsculpture on vertex and disk of pronotum distinct, reticulate; median lobe of aedeagus slender; parameres long, slender.

Differential diagnosis
This species is most similar to P. grandis Grouvelle, 1908; it can be distinguished by the shape of the antennomeres and male genitalia. It differs from all other African Psammoecus by its large size.

Description of holotype
BODY (as in Fig. 4A). Elongate, slender, total length 3.6 mm. Elytra testaceous; humeral swelling and lateral margin dark brown, the dark coloration extended to a broad macula near the middle; apical half of suture and apex dark brown. Head and pronotum reddish brown; lateral margins of pronotum a little darker; anterior and posterior margins of pronotum lighter brown. Antennae testaceous, apex of antennomere 6 and antennomeres 7-10 darkened, antennomere 11 yellowish white. Legs yellow.
HEAD (as in Fig. 4B). Eyes moderately rounded, temples well defi ned and curved, moderately narrowed behind eyes, temple angle 44°; head width 0.78 mm, length 0.46 mm. Puncturation on vertex irregular; punctures almost as large as an eye facet diameter, sometimes contiguous, sometimes leaving spaces the size of their diameter. Pubescence composed of long, semi-erect setae, directed anteriorly; microsculpture on apical part of vertex distinct, reticulate, on basal part of vertex very shallow. Longitudinal impressions on vertex short, slightly curved, barely attaining eye level. Eyes 0.23 mm long, distance of inner margins 0.52 mm. Antennae slender, attaining almost middle of elytra, 1.98 mm long; antennomere proportions: 3.0 : 1.0 : 1.3 : 1.5 : 1.7 : 1.5 : 1.4 : 1.3 : 1.1 : 1.1 : 2.1 (Fig. 4 D). PRONOTUM (as in Fig. 4C). About 1.1 times as wide as head; moderately wider than long; width 0.86 mm, length 0.73 mm. Area close to the posterior angles slightly depressed. Anterior angles separated from the disk by a slightly raised ridge; the small anterolateral space separated by that ridge without microsculpture, bearing 3 short teeth. Left lateral margin with 4, right margin with 5 very short teeth, posterior angle marked by a tooth of same size as lateral teeth. Puncture size on pronotal disk as on vertex, puncturation less dense. Pubescence as on vertex. Microsculpture distinct, reticulate.
ELYTRA. Long and slender, 3.3x as long as pronotum, widest just in front of middle, length 2.44 mm, combined width 1.40 mm. Elytral disk with a fl at depression between fi rst and second third. Rows of punctures on disk about half as wide as interstices; pubescence composed of long, semierect setae; strial setae about 1/3 shorter than interstrial setae; microsculpture restricted to areas near origin of setae, reticulate.
MALE GENITALIA (as in Fig. 4E-G). Parameres in ventral view wide, elongate, lateral face parallel, curved medially towards the apex; in lateral view lancet-shaped, almost straight ventrally and curved dorsally, apical third of dorsal face with short setae, tip bent ventrally. Median lobe slender, evenly narrowed toward apex in dorsal view; in lateral view wide to about the middle, narrowed to a parallel-sided section of about 2/5 its length; apical 1/6 narrowed, dorsal face curved in an S-shape, tip bent ventrally.

Variation
The paratypes vary in body length from 3.60 to 3.92 mm.

Remarks
The general appearance and the unusual structure of the male genitalia make this species a very untypical member of the genus Psammoecus. Its habitus closely resembles that of P. grandis Grouvelle, 1908, but the antennae as well as the male genitalia of P. grandis have an exceedingly different structure (see Fig.  5A-C).

Diagnosis
The following combination of character states is diagnostic for this species: lateral margins of pronotum with distinct teeth; 1 st antennomere 2.3 times as long as 2 nd antennomere; interstices of lateral elytral striae with very small tubercles; anterior angle of pronotum without denticle.

Differential diagnosis
This species differs from all other African Psammoecus by lacking the posterior pronotal denticle and by the shape of the male genitalia.

Etymology
The specifi c epithet refers to the rounded shape of the pronotum.

PRONOTUM (as in
ELYTRA. Oval, widest somewhat behind middle, length 1.60 mm, combined width 1.05 mm. Rows of punctures on disk a bit more than half as wide as interstices; pubescence composed of semierect setae; strial setae slightly shorter than interstrial setae; microsculpture absent. MALE GENITALIA (as in Fig. 6D-E). Parameres with wide basis, lateral face evenly curved, mesal face with rounded projection that bears short, stout spines, apical projection short, bearing one long and one short seta. Lateral faces of median lobe curved, narrowed towards the apex; apex in lateral view widened to form a small knob.

Remarks and comparative notes
Numerous specimens from the Ditsong National Museum of Natural History (Pretoria), were, at fi rst sight, considered to belong to one, or even several, new species. Examination of the aedeagi revealed, however, no differences suffi cient for a separation of these forms from P. laetulus (Fig. 7E-G). Unless

Remarks
The specimen from Cameroon bears a handwritten label 'Psammoechus orbicollis t. Gr. Grouv.', not in Grouvelle's hand. This is to be considered a manuscript name, since no description of a taxon with that name is available.

Discussion
Taking into account the considerable differences in the appearance of African species, it seems likely that Psammoecus is composed of several distinct species groups. However, given the high diversity of Psammoecus in the Oriental and Australian regions and the lack of revisionary work on species from these regions -with the exception of the revisions of Indian Psammoecus by Pal (1985) and Japanese Psammoecus by Yoshida & Hirowatari (2014) -it seems as yet premature to aim at establishing even a 'working taxonomy' on the genus or subgenus level. Hence, future studies will show whether a further subdivision of the genus Psammoecus is justifi ed.