Tarphius (Atlantotarphius) jandiensis, Machado, 2012

Machado, Antonio, 2012, Two new Tarphius species from Macaronesia (Coleoptera, Zopheridae), Journal of Natural History 46 (9 - 10), pp. 637-643 : 639-641

Tarphius (Atlantotarphius) jandiensis n. sp.

( Figure 2 )

Type material

Holotype. Canary Islands ( Spain), Fuerteventura, Jandía, Pico de la Zarza, 810 m (28 ◦ 06 ′ 06 ′′ N, 14 ◦ 21 ′ 19 ′′ W), 1 ♂ 5 March 2011 leg. A. Machado (reg. TFMC/CO15959 Museo de Ciencias Naturales , Santa Cruz de Tenerife) . Paratype, 1 ♂, same data (in my collection) .

Diagnosis

Characterized by its small size (<3 mm), short, parallel and convex body, pronotum laterally rounded and slightly consricted at base, disc subglobose and covered with large flat tubercles; elytra squarish with rounded apex and steep sides; each elytron with two ridgelike longitudinal slight protuberances at third interval (basal and subapical), one at middle of fifth interval, and one indistinct latero-apicad. Granules each bearing a small suberect lanceolate seta.

In the Canary Islands, only Tarphius tenerifensis Franz, 1967 is as small as the new species, but it is much more elongate in shape and belongs to subgenus Tarphius s. str. (without nodules on elytra).

Description (♂)

Length 2.75–2.85, width 1.36–1.42 mm. Tegument pitch brown, anterolateral area of pronotum and nodules on elytra lighter, yellowish brown; appendages rufescent.

Head. Greatest width across eyes; lateral margins before eyes subparallel (slightly swollen), then oblique, anterior margin evenly curved. Surface covered with small granules and setae. Eyes small (smaller than antennal club), moderately protruding. Antennae with segment 2 longer than 3, segments 4 to 6 decreasing in length, segments 7 and 8 subequal.

Pronotum transverse, 1.6 × as wide as long; greatest width at or near middle; sides strongly rounded, more constricted anteriorly than posteriorly, distinctly sinuate before hind angles and these somewhat prominent, obtuse, with blunt tips; anterior angles strongly protruding (tips sharper). Base sinuate, curved posteriad in middle; anterior margin curved forwards. Disc strongly convex, subglobose, not canaliculated at middle, conspicuously covered with large adjacent rounded granules (smaller in anterior region), each bearing a small suberect lanceolate testaceous seta. Lateral marginal area flattened with smaller, less conspicuous granules; granules and setae protruding at margin except at basal third. An incipient posterior fovea at beginning of convex part.

Elytra strongly convex, of squarish outline, somewhat longer than broad (length / width = 1.1), almost two times as long as pronotum, but not much wider. Sides almost parallel (maximum width at basal third), evenly rounded at apical third; sides very steep, particularly at apex (greatest height of abdomen at apical third). Base straight, humeral region widely flattened; humeral angles square, blunt (not protruding). Upper surface with rows of indistinct coalescent granules (less marked and more irregular than on pronotum) with short lanceolate setae and some very minute hairs at their base. These can be seen best with high magnification on granules protruding from lateral rim in dorsal view; setae shorter than distance between them; most are testaceous, some blackish. Nodules elongate and not well developed: in third interval one basal and another apical at the edge of declivity, in fifth interval one median; and in the posterolateral area (7–9 interval) a diffuse and more flattened nodule.

Aedeagus as in Figure 2B . Median lobe acutely pointed, slightly shorter than parameres; ductus ejaculatoris very long, projecting from tegmen by as much as the length of the tegmen.

Comment

A third specimen of Tarphius was collected by my colleague Rafael García in the same locality and date. It is a female of similar general aspect and proportions as the males above described, but with some notable differences:

Pronotum with a median longitudinal depression; margin before hind angles more sharply and deeply sinuate or excavate, thus the hind angles more prominent, acute, and pointed. Basal nodule of elytra on third interval more strongly developed; suture slightly elevated at disc. Dorsal tegument with irregular and abrupt rugosity and tubercles poorly defined except on sides (clearly protruding along the margins). Setae longer (as long as distance between tubercles) and basal ones longer and more easily observed. Abdomen less inflated posteriad, and apical declivity of elytra less pronounced.

It could be a remarkable exception, but Zopheridae in general do not show sexual dimorphism, except for some variations in the tarsi of a few species of Tarphius ( Dajoz, 1977) . Judging from the texture of the tegument, this specimen could be a somewhat aberrant one. However, the differences recorded may fall within the normal variation of the species, which belongs to the group of T. simplex –canariensis ( Franz 1990), where intraspecific variation is high, particularly in sculpture and shape of pronotum. Without studying a longer series, I can not judge if this specimen is the female of Tarphius jandiensis n. sp. or of another coexisting undescribed species.

Bionomics

Tarphius jandiensis . n. sp. was found at Pico de la Zarza ( Figure 3 ), the highest point of the massif of Jandía, a hotspot of biodiversity in the island of Fuerteventura. Many endemic relict species from the more humid former fauna of the island survive at present in the summit of this massif (some also in Betancuria), where the cloud layer of the trade winds maintain a special humid microclimate surrounded by lower arid habitats ( Machado 1976). The specimens were sifted from leaf-litter, decaying branches and dry leaf rosettes of Asteriscus sericeus (Asteraceae) , mixed with bryophytes growing on the trunks of this woody plant.

Figures

Figure 2. Tarphius jandiensis n. sp. imago (A) and aedeagus (B).

Figure 3. Asteriscus sericeus growing in the habitat of Tarphius jandiensis n. sp. at Pico de la Zarza, island of Fuerteventura.