Phyllophaga navassa Woodruff and Steiner, 2011

Woodruff, Robert E. & Warren E. Steiner, Jr., 2011, new species of Phyllophaga Harris from the island of Navassa in the Caribbean (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2011 (157), pp. 1-6 : 1-5

Phyllophaga navassa Woodruff and Steiner , new species

Holotype male. Navassa Island [ U.S.], central forest area, 70M, 18º24.08’N, 75º00.694' W, 28 July 1998, collrs. W. E. Steiner, J. M. Swearingen, et al. / At blacklight in gap in mixed forest ( Ficus , Metopium , Coccoloba, Thrinax ) on limestone. [ U.S. National Museum of Natural History, Smithsonian Institution]. General description ( Fig. 4 , habitus). Medium sized (L. 15mm, W. 8mm), shiny, uniformly dark mahogany brown, convex, nearly glabrous dorsally, unremarkable for genus; genitalia simple, but distinctive, cylindrical, parameres fused ventrally at tip, aedeagus recessed, partly sclerotized, tip upturned ( Fig. 8-15 ).

Head ( Fig. 4, 5 ). Clypeus barely emarginate, lateral angles smoothly rounded, medial indentation slight, margin carinate; clypeal punctures dense, with most coalescing, not setose. Head punctures similar to clypeus, with a few separated by a puncture diameter, and a typical impunctate band near base. Eyes large with setose canthus near center.

Antenna (Fig. 1,3). Nine segmented, 3 club segments nearly equal in length, antennomere 1 nearly equal to next 3 combined, 3rd and 4th more cylindrical and smaller than 2 nd or 5 th; 6 th small and compressed.

Pronotum (Fig. 4,5). Convex, shiny, punctures sparse, shallow, non-setiferous; lateral margin slightly crenulate at origin of long, curved lateral golden setae; anterior margin complete, posterior margin barely indicated, fading medially, smooth with only few scattered punctures.

Scutellum. Triangular, slightly convex, punctate, posteriorly flattened.

Elytra ( Fig. 4 ) Convex, flattened medially, somewhat rugulose horizontally, striae barely indicated, disc glabrous, lateral third and humerus with fine scattered setae; marginal golden setae longest below humerus, similar to pronotal setae. Sutural interval raised, broadest in posterior fifth; terminating in slight projection (not toothed).

Pygidium ( Fig. 6 ). Broadly oval/triangular,evenly convex, shiny, glabrous, with few, shallow, nonsetigerous punctures; posterior lateral margin carinate (inaccurately termed “bead” in older literature) with elongate, golden setae medially.

Legs ( Fig. 2-5, 7 ). Relatively long, especially tarsi; all claws not cleft with sharp termination, middle tooth small, nearer base than tip (anterior right claw in Fig. 3 ).

Anterior tibia tridentate ( Fig. 5 ), anterior tooth elongate, middle sharp, triangular, posterior tooth reduced; teeth spaced nearly equidistant; spur narrow, cylindrical, sharp, half length of 1 st tarsal segment. Anterior tarsal segments cylindrical, nearly equal in diameter, segments 2-4 subequal in length.

Meso-and metatibia with longitudinal carina and incomplete transverse carina ( Fig. 7 ), teeth prominent with long, golden setae. Metatibial spurs ( Fig. 2 ) moveable, long (reaching near middle of tarsal segment 2), narrow, slightly curved, inner surface flattened, inner spur about 20% longer than outer spur; terminus not noticeably notched; fringe of spines 14-16. Metatarsal segments long, cylindrical, 2 nd longer than 1 st; claws as in other legs.

Male Genitalia ( Fig. 8-15 ). Of a simplified form, and unremarkable aedeagus. Parameres symmetrical, lateral views ( Fig. 8-9 ) nearly identical. Caudally ( Fig. 10 ) with large broadly oval opening, parameres fused ventrally; dorsally ( Fig. 14 ) opening v-shaped posteriorly. Each paramere with smoothly rounded lateral carina ( Fig. 12-13 ) about half length; nearly truncate ventrally. Aedeagus cylindrical, partly sclerotized, longer than parameres when extended ( Fig. 8, 9, 11 ). Cylinder twisted and open at tip, with distinctive upturned medial dorsal process, barely protruding in repose ( Fig. 12, 13, 15 ).

Female. Unknown. Because all specimens are males and were collected at light and flight intercept traps, the unknown females may be flightless and subterranean (as are some Hispaniolan high altitude species, see Woodruff and Sanderson 2004). On a small windswept island such adaptation would obviously have survival value.

Relationships. Because 48 species of Phyllophaga are known from the nearest land mass (Hispaniola), it would be significant to establish the relationships of this isolated species. The simplicity of both body habitus and male genitalia imply that it may be a relictual, primitive species. Its colonization of Navassa Island suggests an old, durable, survivor from ancestral stock. DNA investigations may elucidate its relationships.

It does not appear closely related (morphologically) to any other Caribbean Phyllophaga known to us. It is most similar to P. hogardi Blanchard , one of the most abundant, widespread (and economic) species on Hispaniola. It does not possess the distinctive spine-like projections on the elytra sutural tip, and it lacks the “brain-like” mass at the aedeagal tip of that species.

Specimens examined [57]. Holotype and 56 paratype males. All from Navassa Island, collected by W. E. Steiner, J. M. Swearingen, et al. (numbers of paratypes in brackets): Central forest area, 70m., 18 o 24.08’N, 75 o 00.69’W, 28 July 1998, at black light in gap of mixed forest ( Ficus , Metopium , Coccoloba, Thrinax ) on limestone [3]; bluff of southwest rim, 65m., 18 o 23.75’N, 75 o 00.94’W, 25-30 July 1998, flightintercept/yellow pans in Malaise trap, open mixed forest ( Metopium , Coccoloba , Ficus ) at rim of upper terrace, limestone and red oolitic soil [1]; central forest area, 70m., 18 o 23.99’N, 75 o 00.67’W, 26 July-4 August 1998, flight-intercept/yellow pans in Malaise trap in gap of mixed forest ( Ficus , Metopium , Coccoloba , Sideroxylon, Thrinax ) on limestone [3]; same except Malaise trap in gap of mixed forest ( Ficus , Metopium , Coccoloba , Sideroxylon, Thrinax ) on limestone [1]; E. end of east savanna, 65m., 18 o 23.75’N, 75 o 00.52’W, 1 August 1998, at black light at edge of grass savanna and mixed forest ( Ficus , Metopium , Coccoloba ) on limestone and red oolitic soil [3]; near lighthouse, 80m., 18 o 23.82’N, 75 o 00.74’W, 24 July-4 Aug. 1998, taken in Malaise Trap, edge of open weedy scrub and mixed forest ( Ficus , Metopium, Thrinax ) on limestone [2]; same except 26 July 1998, at black light in open weedy scrub near mixed forest ( Ficus , Metopium, Thrinax ) on limestone and red oolitic soil [1]. Paratypes deposited in the U. S. National Museum of Natural History, Washington, D.C., the Florida State Collection of Arthropods, Gainesville, Florida, and the Illinois Natural History Survey, Urbana, Illinois.

Etymology. The specific name navassa is the same as this remote island, the only locality from which it is known. It is applied as a noun in apposition.

Figures

Figure 1-7. Phyllophaga navassa, n.sp. 1) Right antenna. 2) Right metatibial apex. 3) Right protibial claw. 4) Habitus, adult male. 5) Left protibia, tarsus, clypeus (line = 5mm). 6) Pygidium (caudal view). 7) Right metatibia (line = 5mm).

Figure 8-15. Phyllophaga navassa, n.sp., male genitalia. 8,9,11) Aedeagus extended. 10,12-15) Aedeagus in repose. 8) Left lateral. 9) Right lateral. 10) Caudal. 11) dorsal/caudal. 12) Right lateral. 13) Laterocaudal. 14) Dorsal. 15) Left lateral (note upturned aedeagal tip).