Vatellus, AUBE, 1837

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 : 451-452

VATELLUS AUBÉ, 1837

Leucorea Laporte, 1835: 106 (unused name of genus of Vatellini Sharp, objective synonym of Vatellus Aubé ; suppressed by Opinion 1681 ( ICZN, 1992)) (type species: Vatellus tarsatus Laporte, 1835:106 , by monotypy); Laporte, 1840: 167; Gemminger & Harold, 1868: 428; Nilsson et al., 1989: 300; Nilsson, 1991: 36 (case for suppression).

Vatellus Aubé, 1837: 218 (type species: Hydroporus tarsatus Laporte, 1835: 106 by monotypy); Aubé, 1838: 448; Lacordaire, 1854: 414; Gemminger & Harold, 1868: 428; Régimbart, 1878: 454; Sharp, 1882b: 840; Zimmermann, 1919: 124, 1920: 30; Nilsson et al., 1989: 309; Nilsson, 2001: 235. Conserved in Opinion 1681 ( ICZN, 1992).

Macrovatellus Sharp, 1882b: 282 (type species: Macrovatellus marginalis Sharp, 1882b: 284 by subsequent designation of Guignot (1946), not Macrovatellus mexicanus Sharp, 1882b: 284 designated by Leech (1948)); Sharp, 1882a: 8; Zimmermann, 1919: 125, 1920: 30; Nilsson et al., 1989: 300; Nilsson, 2001: 235; Roughley & Larson, 2001: 169, syn. nov.

Platydessus Guignot, 1955: 3 (type species: Platydessus perforatus Guignot, 1955: 4 by monotypy); Spangler, 1966a: 57 (synonymized with Macrovatellus ); Nilsson et al., 1989: 305; Nilsson, 2001:235, syn. nov.

Diagnosis: Members of this genus are differentiable from the other extant genus of the tribe, Derovatellus , in part by the combination of: (1) lateral body outline generally strongly discontinuous, pronotum generally broadest anterior to middle (e.g. Fig. 1); (2) metacoxal lines approximated posteriorly, anteriorly moderately to strongly divergent (e.g. Fig. 176 ); (3) male lateral lobes strongly extended in basal portion, elongate, often with corresponding extension of basal portion of median lobe (e.g. Figs 182–184 ); (4) spermatheca subspherical, only slightly elongate in some species (e.g. Fig. 186 ); (5) apical margin of ventral apex of orifice of speleum distinctly, but variably, lobed (e.g. Fig. 209 ).

Distribution: Members of Vatellus occur in the New World from southern Texas south throughout Central and South America to Argentina. Most of its members occur in lowland, subtropical or tropical wetlands.

Taxonomic history: The oldest name for this genus is Leucorea Laporte (1834, 1835 ), but this name was never used. Instead, Vatellus Aubé became the most commonly used name for the taxon. Both names included only the type species Hydroporus tarsatus Laporte (by monotypy), until now. Eventually, Nilsson et al. (1989) suggested conservation of the name Vatellus . Nilsson (1991) formally proposed doing so and the name was conserved ( ICZN, 1992). However, evidence from this project indicates that Vatellus tarsatus is nested well within a group of species historically placed in a separate genus, Macrovatellus Sharp , making the latter genus paraphyletic ( Fig. 316 ). Vatellus was delimited based on the character state of distinctive, abrupt posterior margins on the abdominal sterna. However, in other respects, V. tarsatus resembles members of Macrovatellus , and together the species are monophyletic sharing several distinctive synapomorphies (see Cladistic analysis below). Therefore, I have chosen to synonymize the two genera. The conserved name Vatellus has priority over Macrovatellus . Platydessus was described for the species V. perforatus (Guignot) and placed in the tribe Bidessini . However, Spangler (1966b) recognized that the genus belongs in Vatellini and synonymized the name with Macrovatellus .

Natural history: Most of the members of this group occur in ponds, marshes and small, slow streams with considerable dense vegetation.

Discussion: Members of this genus have a number of external characters useful for distinguishing between species or groups of species. However, positive identification of species generally requires dissection of male or female genitalia and examination of the speleum.

Figures

Figures 174–181. Vatellus haagi. 174, dorsal habitus; 175, elytral sculpture in area indicated on habitus by dotted square; 176, medial portion of metacoxae; 177, metatrochanter and metafemur, anterior aspect; 178–179, tarsomeres, dorsal aspect; 178, male; 179, female, A, protarsus; B, mesotarsus; 180, sternum VI, ventral aspect; 181, speleum abdominal sterna V, VI, dorsal aspect.

Figures 182–188. Vatellus haagi. 182–185, male genitalia; 182, median lobe, right lateral aspect; 183, median lobe, ventral aspect; 184, right lateral lobe, lateral aspect; 185, apex of median lobe, ventral aspect; 186–188, female genitalia; 186, ventral aspect; 187, bursa copulatrix, left lateral aspect; 188, spermatheca and associated structures, dorsal aspect; BC, bursa copulatrix; FC, fertilization sac sclerite; FD, fertilization duct; GC, gonocoxa; GS, gonocoxosternite; ID, intermediate duct; RA, rami; RE, receptacle; SD, spermathecal duct; SP, spermatheca; TP, truncate spermathecal process.

Figures 203–210. Vatellus perforatus. 203, dorsal habitus; 204, elytral sculpture in area indicated on habitus by dotted square; 205, medial portion of metacoxae; 206, metatrochanter and metafemur, anterior aspect; 207–208, tarsomeres, dorsal aspect; 207, male; 208, female, A, protarsus; B, mesotarsus; 209, sternum VI, ventral aspect; 210, 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.