Psammoecus laetulus Grouvelle, 1914

Karner, Michael, 2012, A revision of African Psammoecus (Coleoptera, Silvanidae) and descriptions of two new species from the collection of the Musée royal de l’Afrique centrale, European Journal of Taxonomy 17, pp. 1-31 : 7-9

Psammoecus laetulus Grouvelle, 1914

( Fig. 3 )

Psammoecus nitescens Grouvelle, 1914: 149 . syn. nov.

Material examined

Lectotype

♀, by present designation: ‘25’ [hand written on specimen’s mounting label], ‘ Type | H.T.’ [round label with red border], ‘Seychelle Islands. | Percy Sladen | Trust Expedition | 1913.-170’, ‘ Psammoecus | laetulus Grouv. | TYPE | Figured Specimen’ [not Grouvelle’s hand; last line on reddish piece of paper glued to the label], ‘ Psammoecus | laetulus | TYPE Grouv.’ [Grouvelle’s hand, ‘TYPE’ printed on blue piece of paper glued on the label, mounted facing down], ‘Silhouette, 1908. | Seychelles Exp.’ [mounted facing down], ‘SYN- | TYPE’ [round label with blue border] ( BMNH)

Other material

1 spm ‘25’ [hand written on specimen’s mounting label], ‘Type | H.T.’ [round label with red border], ‘Seychelle Islands. | Percy Sladen | Trust Expedition | 1913.-170’, ‘Silhouette, 1908. | Seychelles Exp.’ [mounted facing down], ‘ Psammoecus | nitescens | TYPE Grouv.’ [Grouvelle’s hand, ‘TYPE’ printed on blue piece of paper glued on the label], ‘ Psammoecus | nitescens | Grouvelle | TYPE Figured’ [not Grouvelle’s hand; ‘Figured’ printed on reddish piece of paper glued to the label, mounted facing down], ‘SYN- | TYPE’ [round label with blue border] ( BMNH). This specimen is hereby designated to be the lectotypus of Ps. nitescens . 5 spms ‘Seychelle Islands. | Percy Sladen Trust | Expedition | 1913.- 170’, ‘ Psammoecus | nitescens | A. Grouvelle | Paratype’, ‘Seychelle Islands. | Percy Sladen | Trust Expedition | 1913.-170’, ‘SYN- | TYPE’ [round label with blue border] ( BMNH). These specimens are hereby designated to be paralectotypes of Ps. nitescens . 96 spms ‘Iles Séchelles – Mahé | Centre: Morne Séch- | ellois, for. Endémique, | 750 m. 13/ 17.VII.1972 ’, ‘Coll. Mus. Tervuren | Miss. zool. belge aux | Séchelles – PLG Benoit | et. J. J. Van Mol’ ( MRAC, 4 spms in coll. MKF).

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.

HEAD. Transverse, 0.69-0.75 mm wide, 0.39-0.48 mm long, 1.53-1.77 times as wide as long. Eyes large, protuberant, 0.21-0.23 mm long, distance of inner margins 0.43-0.48 mm. Puncturation on vertex coarse, moderately dense; pubescence composed of long, semierect setae, directed anteriorly; microsculpture absent. Longitudinal impressions on vertex distinct, almost parallel, attaining middle of eyes. Antennae long and slender, 1.45-1.63 mm long, antennomere proportions as follows: 2.7: 1.0: 1.2: 1.7: 1.7: 1.6: 1.4: 1.2: 1.2: 1.1: 2.3.

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 five 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.

ELYTRA. Oval, length 1.54-1.88 mm, combined width 1.10-1.18 mm, 1.40-1.52 times as long as their combined width. Rows of punctures on disc slightly narrower than interstices; pubescence composed of long, semi-erect setae, directed anteriorly; microsculpture absent.

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.

Figures

Fig. 3. Psammoecus laetulus Grouvelle, 1914, specimen from Mahé. A. Habitus. B. Left antenna. C. Parameres. Scale line A, B: 1 mm; C: 0.2 mm.