Vatellus sahlbergi Miller, 2005

Miller, Kelly B., 2005, Revision of the New World and south-east Asian Vatellini (Coleoptera: Dytiscidae: Hydroporinae) and phylogenetic analysis of the tribe, Zoological Journal of the Linnean Society 144 (4), pp. 415-510 : 454-459

VATELLUS SAHLBERGI (SHARP, 1882) COMB. NOV.

Macrovatellus sahlbergi Sharp, 1882b: 283 ; Zimmermann (1920): 30; Guignot, 1957: 3; Trémouilles, 1995: 27.

Type information: Lectotype (designated here to clarify assignment of this name with this species) ♂ in BMNH labelled, ‘ Type [circular disc with red border]/ 440 [handwritten]/ S.America: Brazil. [with green line transversely across middle of label]/ Petropolis, March Sahlberg. 1850 [handwritten]/ Petropolis March 1850 Sahlberg. [handwritten]/Sharp Coll 1905–313./Type 440 Macrovatellus Sahlbergi Petropolis. [handwritten]/SYN- TYPE [circular disc with blue border]/LEC- TOTYPE Macrovatellus sahlbergi Sharp 1882 . des. K.B. Miller 2002 [red label with black line border].’ Sharp had two specimens upon which he based his description, and a single paralectotype with similar label information accompanies the lectotype in BMNH.

Type locality: Brazil, Petropolis. Diagnosis: This species is very large and has the outline of the body strongly discontinuous between the pronotum and elytra in dorsal aspect. In lateral aspect the median lobe is long, slender, straight and apically abruptly narrowed with a minute, apical point ( Fig. 125 ). In ventral aspect the median lobe is long and slender with the lateral margins parallel-sided and with the apex nearly truncate and with a small, medial process ( Figs 126, 128 ). The lateral lobe is broad and bears a large field of dense setae apically ( Fig. 127 ) .

Description:

Habitus. Body outline strongly discontinuous in dorsal aspect, lateral margins of elytra strongly rounded ( Fig. 117 ), dorsoventrally not compressed. Measurements are given in Table 1.

Coloration. Head dark red; pronotum dark red, nearly black; elytron dark red with apical, lateral and humeral small, pale maculae ( Fig. 117 ); venter and appendages dark red.

Sculpture and structure. Head finely and evenly punctate, punctures slightly finer anteriorly, surface shiny and smooth between punctures; anterior clypeal margin swollen and rounded, not anteriorly produced; eyes moderately sized and somewhat protuberant ( Fig. 117 ). Pronotum medially densely punctate, punctures moderately sized, setae short, inconspicuous, surface between punctures alutaceous, conspicuously rough, partially obscuring punctures, laterally punctures nearly entirely obscured; pronotum somewhat cordate, very broad, broadest slightly anterad of middle, margins strongly rounded, posterior angles obtusely angled ( Fig. 117 ); lateral bead obscured; transverse sulcus present, distinct, pronotum slightly swollen medially. Elytron densely punctate, punctures moderately coarse, covering entire surface, strongly obscured apically, setae short, inconspicuous, surface between punctures alutaceous similar to pronotum ( Fig. 118 ); with indistinct, longitudinal raised line medially on elytron. Prosternum short, rough, glabrous; prosternal process relatively narrow, medially tectiform, apex narrowly triangular, pointed, flattened. Metasternum rugulose and alutaceous, punctation entirely obscured and not evident; anteromedial margin laterally somewhat compressed, but not ventrally expanded. Abdominal sterna with surface irregularly rugulose and alutaceous, punctation obscured; sixth sternum with apical lobe broad, apex broadly rounded; speleum long, relatively slender, apex narrowly rounded. Metacoxa with medial portion with surface conspicuously rugose and alutaceous, punctation fine; metacoxal lines approximated basally, broadly divergent anteriorly ( Fig. 119 ); medial portion rugulose, finely punctate. Metatrochanter moderately elongate and distinctly offset, apex rounded ( Fig. 120 ); metatarsal claws finely pectinate.

Male genitalia. Median lobe in lateral aspect relatively straight throughout length, lateral margins parallel, basal portion short, narrow; apically abruptly narrowed to sharply curved apex, without setae ( Fig. 125 ); in ventral aspect with lateral margins parallel, apex truncate with narrow medial spinous or truncate process ( Figs 126, 128 ). Lateral lobe with apical portion very broad, apex broadly rounded, with

mm

moderately dense region of fine setae apically and along apicodorsal margin; long, stout, subapical spine absent ( Fig. 127 ).

Female genitalia. Gonocoxosternite moderately broad, apical angle rounded, anterior margin curved, anterior lobe long, relatively slender, posterior margin with many stout setae ( Fig. 129 ). Gonocoxa long, apex rounded, apodeme long and relatively slender ( Fig. 129 ). Bursa copulatrix broad, relatively large, with anterior thickened region around orifice of spermathecal duct ( Fig. 129 ); spermathecal duct long, slender; receptacle large, subequal in size to spermatheca, subspherical ( Fig. 129 ); intermediate duct moderately long, sinuate near spermatheca ( Fig. 130 ); spermatheca subspherical, large; fertilization duct moderately long, slender ( Fig. 129 ).

Sexually dimorphic characters. With brushes of setae on mesotrochanter and base of mesofemur well developed, brush on mesofemur forming an elongate cup-shape. Male with pro- and mesobasotarsomeres ( Fig. 121 ) broader and more expanded than in female ( Fig. 122 ).

Distribution: This relatively rare species is known from southern Brazil and Paraguay ( Fig. 311 ). This species was recorded from Bolivia by Guignot (1957), although the identification may be in error.

Phylogenetic relationships: As with V. ventralis , this species occupies an unresolved, ambiguous position basally within the genus ( Fig. 316 ). Unlike that species, both males and females are known, but the species lacks some of the more distinctive characters used to group taxa within Vatellus . In the most parsimonious trees, the species is generally associated with the V. mexicanus clade either as sister to it in a clade or with it as a paraphyletic grade with it as sister to the remaining Vatellus ( Figs 320 –324).

Material examined: Brazil: Country only (1, USNM) ; Petropolis, March 1850 (1, BMNH) . Paraguay: Hohenau. Alto-Parana, 28 August, H Jacob (3, BMNH) .

Figures

Figure 311. Vatellus species, distribution. - = V. lateralis, Δ = V. maculosus, • = V. sahlbergi.

Figures 125–130. Vatellus sahlbergi. 125–128, male genitalia; 125, median lobe, right lateral aspect; 126, median lobe, ventral aspect; 127, right lateral lobe, lateral aspect; 128, apex of median lobe, ventral aspect; 129–130, female genitalia; 129, ventral aspect; 130, spermatheca and associated structures, dorsal aspect.

Figures 117–124. Vatellus sahlbergi. 117, dorsal habitus; 118, elytral sculpture in area indicated on habitus by dotted square; 119, medial portion of metacoxae; 120, metatrochanter and metafemur, anterior aspect; 121–122, tarsomeres, dorsal aspect; 121, male; 122, female, A, protarsus; B, mesotarsus; 123, sternum VI, ventral aspect; 124, speleum abdominal sterna V, VI, dorsal aspect.

Figures 315–316. Vatellini species, consensus cladograms. 315, Consensus cladogram of 72 most parsimonious cladograms (length = 78, CI = 67, RI = 92) resulting from cladistic analysis of Vatellini including Calicovatellus petrodytes. 316, Consensus cladogram of five most parsimonious cladograms (length = 74, CI = 70, RI = 93) resulting from cladistic analysis of Vatellini not including Calicovatellus petrodytes. Numbers above branches are Bremer support values.