A revision of African Psammoecus (Coleoptera, Silvanidae) and descriptions of two new species from the collection of the Musée royal de l’Afrique centrale

A revision of the known African species of Psammoecus is given, including redescriptions and illustrations of diagnostic characters. Extensive material from the Musée royal de l’Afrique centrale (Tervuren) is studied. Two new species are described: Psammoecus leleupi sp. nov., and Ps. luchti sp. nov. Four specifi c names are synonymized: Psammoecus excellens Grouvelle, 1908 = Ps. trimaculatus Motschulsky, 1858; Ps. alluaudi Grouvelle, 1912 = Ps. trimaculatus Motschulsky, 1858; Ps. longulus Grouvelle, 1878 = Ps. longicornis Schaufuss, 1872; Ps. nitescens Grouvelle, 1914 = Ps. laetulus Grouvelle, 1914. A key to the African species is provided.


Introduction
While examining extensive material of African Psammoecus Latreille, 1829 from the collection of the Musée royal de l'Afrique centrale (Tervuren, Belgium) it came clear that any attempt to determine the material at hand required studies of type material. Since the studies of Grouvelle (see references), no work was done on African species of this genus. The available papers, however, were found to be of little practical help, refl ecting the taxonomic standards of the late 19th century. They frequently show a lack of detail in descriptions and diagnostic content.

Material and Methods
Specifi c identifi cation of Psammoecus is often possible by use of external characters, viz. general body shape, the pattern and form of pronotal teeth, and the puncturation of the body surface. The male genitalia provide diagnostic characters especially in the shape of the parameres. Determination of single female specimens was sometimes found impossible, since female genitalia were not found to provide useful characters. An overview considering the general structure of the genitalia of Psammoecus is given by Pal (1985).
Although the genital structures are small and delicate, preparation of the genitalia is not very diffi cult. The animal is softened by soaking it in water overnight. The abdomen is separated from the body by use of a very fi ne insect pin, and macerated in warm, 5% solution of caustic potash (KOH) for few minutes. After rinsing in water, the abdomen is dissected in a drop of 5% acetic acid to isolate the genitalia. It should never be attempted to pull the genitalia out of the abdomen, since this would involve a high risk of the structures, especially the setae, being destroyed. The isolated genitalia are embedded in a fl at drop of embedding medium (either canada balsam or a water-soluble medium, e.g. as described by Franzen & Karner 1998) on a piece of transparent cellulose acetate fi lm that is put on the specimen's insect pin.
Drawings were made by aid of microscopes and a camera lucida at magnifi cations of 50 times and 400 times, respectively. The microsculpture of the body surface was studied at a magnifi cation of 80 times. The lateral teeth bordering the pronotum were numbered, using roman numerals, beginning anteriorly, behind the group of very small teeth that are located at the anterior angle of the pronotum.
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.
Material is listed according to the localities, sorted from north-east to south-west. All label data are given. The labels are cited beginning with the uppermost one, the respective lines are separated by '|'. If words or single characters could not be deciphered, the characters are represented by a corresponding number of '?' within squared brackets. Also, comments on label colors, label shapes, and other regarding the respective specimen are included in squared brackets.
Specimens from the following collections were studied:

Redescription
BODY. Elongate-oval, total length 2.40-3.05 mm ( Fig. 2A). Surface yellowish to reddish brown, elytra with variable patterns of maculae; the basic pattern consists of brown or blackish brown maculae at the elytral bases, sutures, lateral margins and apices. Specimens of lighter colour show no darker coloration on anterior half of elytral suture and posterior half of lateral margins; very dark specimens have dark elytra with light brown maculae on the anterior and posterior aspects of the disk. Antennae as in Fig. 2B, yellowish brown; 6 th to 10 th and apical half of 5 th antennomere brown to blackish-brown, 11 th antennomere yellowish brown, sometimes a little lighter than basal antennomeres. PARAMERES. Slender, short, with dense rows of small setae at the inner margins of their bases and two larger setae at their apices. (Fig. 2C).

Differential diagnosis
Ps. laetulus differs from Ps. hacquardi, Ps. personatus, and Ps. leleupi sp. nov. by the maximum pronotal width being located in the anterior third. It differs from Ps. personatus also by shorter lateral teeth of pronotum, wider elytral striae, and more extensive dark elytral markings; from Ps. leleupi sp. nov. also by lateral margin of pronotum less curved, slender parameres with shorter setae; from Ps. marginicollis by 1 st antennomere being more than two times as long as 2 nd ; from Ps. parallelus by more extensive dark maculae on elytra, darkened elytral basis and slender shape of parameres; from Ps. luchti sp. nov. by less rounded lateral margin of pronotum, darkened elytral basis, and more slender parameres.

Redescription
BODY. Oval, total length 2.35-2.95 mm (Fig. 3A), head and pronotum blackish-brown with the head in most specimens somewhat brighter; elytra yellowish brown with darkened humeral area, dark lateral margin, a wide transversal band behind the middle and apex dark. In many specimens the darkened areas on the elytra are enlarged, leaving only bright maculae on the anterior and posterior portions of the elytra. Antennae as in Fig. 3B, bright reddish-brown, 7 th to 10 th antennomeres and apex of 6 th antennomere blackish-brown, 11 th antennomere bright, almost white. PRONOTUM. Subquadrate, posterior margin with shallow impressions; 0.66-0.78 mm wide, 0.53-0.63 mm long, 1.15-1.33 times as wide as long. Anterior angles with small group of teeth; margins with fi ve lateral teeth; tooth I small, only slightly bigger than teeth of anterior group; tooth II somewhat bigger, tooth III biggest, teeth IV and V small; posterior angle with very small tooth. Puncturation and pubescence on pronotal disc in most specimens as on vertex, sometimes a little coarser. Microsculpture variable, mostly absent, in few specimens shallow, reticulate.
PARAMERES. Slender, narrowing gradually towards apex; inner margins with numerous small setae, few setae on outer margins of apical struts; apex with single large seta (Fig. 3C).

Remarks
Both Ps. laetulus and Ps. nitescens are described in the same paper by Grouvelle (1914). Due to the name Ps. laetulus preceding in the original article, it is considered to be the valid name for this taxon, with Ps. nitescens being a synonym. Grouvelle, 1919 (

Differential diagnosis
Differs from Ps. personatus and Ps. leleupi sp. nov. by the shorter lateral teeth of pronotum; from Ps. leleupi sp. nov. also by narrower elytral striae, round dark maculae in posterior third of elytra, darkened suture near elytral apex, and the absence of a darkened area at bases of elytra; from Ps. hacquardi and Ps. laetulus by round dark maculae in posterior third of elytra, darkened suture near elytral apex, the absence of a darkened area at bases of elytra and very wide bases and club-shaped extensions of parameres; from Ps. marginicollis by 1 st antennomere being almost three times as long as 2 nd and from Ps. marginicollis and Ps. luchti sp. nov. by very wide bases and club-shaped extensions of parameres.

Description
BODY. Elongate oval, total length 2.80-3.20 mm (Fig. 5A). Elytra with dark brown to blackish maculae at base, on the disc and with a dark apex. The large maculae on the disc often form a transverse band, connected to the apical maculae by the darkened suture. Head and pronotum darker than the bright areas of elytra, mostly even darker than the elytral maculae. Antennal coloration variable, 7 th to 9 th and basis of 6 th antennomere darkened, 10 th and 11 th antennomere very bright, often almost white. Some specimens with darkened 10 th antennomere.  PRONOTUM. Broad, near apical margin and apical angles with shallow impressions; width 0.83-0.91 mm, length 0.59-0.66 mm, 1.33-1.51 times as wide as long. Anterior angles with distinct group of comparatively big teeth, lateral margins with four distinct triangular teeth; tooth I short, tooth II somewhat longer, tooth III the longest, tooth IV a bit shorter than tooth III, but longer than tooth II; posterior angle with distinct angular tooth. Puncturation and pubescence on pronotal disc as on vertex. Microsculpture absent.
PARAMERES. With wide, stout base and club-shaped apical extension. Inner margin of base with 3-4 longer and numerous short setae; inner margin of extension with numerous small setae, apical portion of extension with 2-3 long setae (Fig. 5C).

Etymology
The name is dedicated to Wilhelm Lucht , who provided the author with much helpful advice in the course of his fi rst steps into entomology.

Diagnosis
Lateral margins of pronotum rounded, bearing fi ve distinct teeth with wide bases. Elytra elongate-oval, bright reddish-brown with dark, transverse band at beginning of posterior portion, sometimes with darkened suture near elytral apex; striae on elytral disc slightly wider than interstices. Parameres small, elongate, spatula-shaped.

Differential diagnosis
Ps. luchti sp. nov.differs from Ps. simoni Grouvelle, 1892 by the elytral striae being only slightly wider than the interstices, elytra being more elongate, elytral basis not darkened. It differs from Ps. hacquardi and Ps. marginicollis by wider bases of lateral teeth of pronotum; from Ps. hacquardi also by wider elytral striae and elytral basis not darkened; from Ps. marginicollis, Ps. parallelus, Ps. leleupi sp. nov., Ps. simoni, and Ps. laetulus by spatula-shaped parameres. It further differs from Ps. leleupi sp. nov. and Ps. laetulus by elytral basis not darkened; from Ps. personatus by shorter lateral teeth of pronotum with wider bases; and from Ps. laetulus by more rounded lateral margin of pronotum.
HEAD. Very wide, with large, protuberant eyes, temples narrowed immediately behind eyes. Head width 0.79-0.88 mm, length 0.44-0.48 mm, 1.75-1.96 times as wide as long. Eyes 0.20-0.23 mm long, distance of inner margins 0.50-0.60 mm. Puncturation on vertex coarse, relatively dense, distance between punctures irregular; pubescence composed of long erect setae, directed anteriorly; microsculpture absent. Longitudinal impressions on vertex distinct, short, attaining second third of eyes. Antennae as in Fig. 6B, long and  PRONOTUM. Broad, shallowly impressed near apical margin and apical angles, width 0.80-0.96 mm, length 0.60-0.73 mm, 1.28-1.40 times as wide as long. Anterior angles with group of very small teeth, lateral margins with fi ve distinct, triangular teeth; tooth I small, tooth II larger, tooth III largest, tooth IV slightly smaller than tooth III, tooth V smallest; posterior angle with very small angular tooth. Puncturation and pubescence on disc as on vertex; microsculpture absent.
ELYTRA. Elongate oval, length 1.85-2.05 mm, combined width 1.15-1.40 mm, 1.44-1.65 times as long as their combined width. Rows of punctures on disc slightly wider than interstices, pubescence composed of semierect setae that are somewhat shorter as on head and pronotum; microsculpture absent.
PARAMERES. Small, elongate; base less than 2 times as wide as apical extension, inner margins with few short setae, inner portion of apex with four longer setae, outer portion with one shorter and one longer seta (Fig 6C). Grouvelle, 1908 (

Differential diagnosis
Ps. grandis resembles Ps. longicornis Schaufuss, 1872 and Ps. lateralis (Grouvelle, 1899), but differs by the presence of small lateral teeth of pronotum. It differs from Ps. longicornis also by the very large and curved parameres with very short extensions.

Redescription
BODY. Slender, narrow, total length 3.4-4.2 mm (Fig. 7A), surface yellowish-brown, elytra with dark maculae of variable shape; some immature specimens only with a darkish macula in the posterior half of elytra, other specimens with posterior half of elytral suture and elytral maculae blackish-brown. 7 th to 10 th antennomere and apex of 6 th antennomere darkened, 11 th antennomere brighter than basis of antennae.
HEAD. With comparatively small eyes and broad, curved temples; width 0.80-0.89 mm, length 0.45-0.48 mm; 1.71-1.85 times as wide as long. Eye length 0.23-0.25 mm, distance of inner margins 0.48-0.56 mm. Puncturation on vertex irregular, pubescence composed of short, recumbent setae, directed anteriorly; microsculpture well defi ned, reticulate. Longitudinal impressions on vertex short, curved, almost attaining the anterior third of eyes. Antennae as in Fig. 7B, short, length 1.58-2.00 mm, 1 st antennomere very long and slender. Antennomere proportions of holotype as follows: 3.33 : 1 : 1.17 : 1.5 : 1.2 : 1.7 : 1 : 1 : 1.8 : 1: 2.17. PRONOTUM. Subquadrate, width 0.89-1.03 mm, length 0.75-0.90 mm, 1.14-1.23 times as wide as long. Surface uneven with fl at impressions near the posterior margin close to the posterior angles as well as in the middle of the posterior margin. Less distinct impressions also close to the anterior margin, in some specimens also in the middle of the pronotal disc. Posterior angle with a very small group of teeth, lateral margins with four to fi ve very short lateral teeth, posterior angle almost rudimentary. The holotype shows an asymmetrical tooth pattern with different numbers and location of lateral teeth on the two sides of the pronotum. Puncturation slightly coarser and denser than on vertex, pubescence as on vertex; microsculpture well defi ned, reticulate.
ELYTRA. Narrow, slender, length 2.10-2.67 mm, combined width 1.35-1.60 mm, 1.50-1.81 times as long as their combined width. Rows of punctures on the disc a little narrower than interstices. Pubescence rather fl at, consisting of long setae. Microsculpture visible only in few specimens, very weak, reticulate.

Differential diagnosis
Ps. marginicollis differs from Ps. personatus and Ps. leleupi sp. nov. by the shorter lateral teeth of pronotum; from Ps. laetulus and Ps. parallelus by 1 st antennomere being two times as long as 2 nd ; from Ps. hacquardi by wider, less elongate parameres and longer antennae; from Ps. leleupi sp. nov. by narrower elytral striae and parameres without club-shaped extension; from Ps. parallelus by wide parameres without club-shaped extension; from Ps. luchti sp. nov. by narrower bases of lateral teeth of pronotum and wider, less elongate parameres.

Redescription
BODY. Elongate oval, total length 2.50-3.50 mm (Fig. 8A). Surface yellowish to reddish brown, some specimens considerably darker with lateral margins of pronotum blackish brown. Elytra with variable pattern of dark maculae; darker specimens with wide, horizontal maculae in the middle of the elytra and dark apical portion of elytral suture; the basal portion of the eltral suture not darkened. Specimens of lighter colour with reduced maculae on the elytral discs and only slightly darkened or light apical portion of elytral suture. Few specimens without elytral maculae. Antennae yellowish or reddish brown, 7 th to 10 th antennomere dark brown or black, 11 th antennomere yellowish brown, lighter than basal antennomeres. PRONOTUM. Subquadrate, width 0.70-0.85 mm, length 0.56-0.70 mm, 1.16-1.42 times as wide as long. Surface even. Anterior angle with distinct group of small teeth. Lateral margin with fi ve distinct, short teeth; tooth I short with wide base, tooth II a little larger, teeth III and IV still a little larger, triangular with wide bases, tooth V about as big as tooth II. Posterior angle with very small tooth. Puncturation on pronotal disc coarser and denser as on vertex, pubescence as on vertex. Microsculpture variable, in most specimens well defi ned, reticulate, in some specimens hardly visible or absent.

Remarks
The shape of the parameres was found to vary to a small degree. So far, the material at hand was not suffi cient to decide wether this variability has specifi c importance, hence all specimens mentioned here were determined to be conspecifi c with Ps. marginicollis. (Grouvelle, 1899) (

Differential diagnosis
Ps. lateralis resembles Ps. longicornis, but differs by the smaller and less dense puncturation on head, pronotum, and elytral discs, and by the longer antennae.
It differs from Ps. grandis by absence of lateral teeth of pronotum.

Redescription
BODY. Elongate-oval, total length 3.60 mm (Fig. 9A). Surface yellowish brown with elytral margin and a round macula on posterior third of elytra dark brown.
HEAD. With long, slightly rounded temples; width 0.79 mm, length 0.48 mm, 1.65 times as wide as long. Eyes moderately protuberant, 0.4 mm long, distance of inner margins 0.53 mm. Puncturation on vertex of moderate density, punctures small, distance between punctures variable. Pubescence composed of short semierect setae, directed anteriorly; microsculpture very distinct, reticulate. Longitudinal impressions on vertex short, distinct, attaining the anterior quarter of the eyes. Antennae as in Fig. 9B PRONOTUM. Subquadrate, width 0.86 mm, length 0.75 mm, 1.15 times as wide as long. Anterior and posterior angles with distinct groups of small teeth, lateral teeth absent. Puncturation on pronotal disc sparser as on vertex, punctures of same size as on vertex. Pubescence shorter and less erect as on vertex; microsculpture distinct, reticulate.
ELYTRA. Elongate, length 2.35 mm, width 1.28 mm, 1.84 times as long as combined width. Rows of punctures on disc distinctly narrower than interstices. Pubescence composed of only slightly erect setae; microsculpture hardly visible, very shallow, reticulate.  Schaufuss, 1872 (Fig. 10) ELYTRA. Oval, length 1.68-2.10 mm, width 0.95-1.50 mm, 1.40-1.80 times as long as wide. Rows of puctures somewhat wider than interstices. The pubescence of the studied specimens almost completely damaged, as far as visible, the setae are short and recumbent; microsculpture absent.

Psammoecus longicornis
PARAMERES. With wide base and slender apical extension. Inner margin with numerous short setae, apex with single long seta (Fig. 10C).

Remarks
Pal (1985) gave a redescription of Ps. trimaculatus based on material from Motschulsky's collection (Museum Moscow) that he accepted as type material. He did not designate a lectotype. The material consisted of fi ve specimens mounted on a single label (Pal 1996, personal communication).
It was not possible for the present author to see this material, but he had the opportunity to study a single, female specimen from Motschulsky's collection (ZMUM). This specimen is not assumed to be a type, while the material mentioned by Pal may be discovered again. Pal (1985) provided detailed fi gures of Ps. trimaculatus, including the male genitalia, and gives an overview on the taxonomy. He states that it occurs in India, Nepal, Bhutan, Sri Lanka, Myanmar, Malaysia, Australia, Japan, and Madagascar. Recently, it has also been recorded as being established in Brasil (Thomas & Yamamoto 2007

Differential diagnosis
Ps. simoni differs by its short oval habitus and the short, stout parameres that are fused with the basal piece from all other African Psammoecus. The wide-based pronotal teeth resemble Ps. luchti sp. nov., it differs by the elytral striae being considerably wider than interstices, elytra being shorter, darkened basis of elytra, parameres short, stout and fused with basal piece.

Redescription
BODY. Oval, total length 2.13-3.00 mm (Fig. 11A). Surface yellowish-brown, sometimes reddish-brown, elytra with brown or blackish-brown maculae: humeral swelling, a transverse band in the middle of the elytra, the elytral suture along the posterior two thirds and the elytral apex are dark. Base of antennae yellowish or reddish brown, 6 th to 10 th antennomere darkened, 11 th antennomere yellowish-white, some specimens with light apex of 10 th antennomere.

Remarks
In his original description, Grouvelle (1892) spells the name 'simonis'. However, on the labels that Grouvelle added to the syntypes as well as in a later paper (Grouvelle, 1908c), he spells the name 'simoni'. Pal (1985) also uses the latter spelling. Hence the present author considers 'simonis' to be a misprint and proposes to spell the name in accordance with Grouvelle (1908c) and Pal (1985). Grouvelle, 1882 (

Differential diagnosis
Ps. spinosus differs by the very characteristic shape of the pronotum and the distinctly toothed elytral margins from all other African Psammoecus.

Redescription
BODY. Oval, total length 2.40-3.15 mm (Fig. 12A), reddish-brown, elytra with darkened basis and with dark lateral macula near their middle, connected to the darkened suture in posterior half which is connected to another lateral macula close to the apex; the maculae forming a roughly x-shaped pattern on posterior two thirds of elytra. Antennae reddish-brown, 7 th to 10 th antennomeres darker brown, 11 th antennomere bright yellowish, almost white.
HEAD. Wide, temples strongly narrowed immediately behind eyes; width 0.60-0.75 mm, length 0. PRONOTUM. Transverse, posterior and lateral margins with distinct impressions, close to the middle of the anterior margin with shallow impression; width 0.65-0.83 mm, length 0.45-0.58 mm, 1.38-1.44 times as wide as long. Anterior angle with very distinct group or large teeth; lateral margin characteristic pattern of four teeth; tooth I large with wide basis, teeth II and III almost fused, forming a large forked tooth, tooth IV as large as tooth I; posterior angle with small group of teeth. Anterior margin with a small short tooth right between anterior group of teeth and middle of anterior margin. Puncturation on disc somewhat coarser as on vertex, pubescence as on vertex, microsculpture absent.
ELYTRA. Oval, length 1.55-2.08 mm, combined width 0.98-1.40 mm, 1.46-1.59 times as long as combined width. Rows of punctures on the disc about as wide as interstices; pubescence composed of long semierect setae, directed posteriorly; interstices of lateral rows of punctures with tubercles that are enlarged to form distinct teeth; towards the elytral disc, these teeth become successively smaller. Microsculpture absent.
PARAMERES. Simple, narrowed towards apex, without well-defi ned basal part. Inner portion of parameres with numerous small setae; apex with one large seta (Fig. 12C).

Remarks
It has not been possible to locate and study type material of Ps. spinosus. However, Grouvelle (1882) provides an illustration that leaves little doubt regarding the identity of this species, given its peculiar habitus.