Hoplopleura leucomus, Musser, Guy G., Durden, Lance A., Holden, Mary Ellen & Light, Jessica E., 2010

Musser, Guy G., Durden, Lance A., Holden, Mary Ellen & Light, Jessica E., 2010, Systematic Review of Endemic Sulawesi Squirrels (Rodentia, Sciuridae), with Descriptions of New Species of Associated Sucking Lice (Insecta, Anoplura), and Phylogenetic and Zoogeographic Assessments of Sciurid Lice, Bulletin of the American Museum of Natural History 2010 (339), pp. 1-260 : 1-260

Hoplopleura leucomus , new species

HOLOTYPE AND TYPE LOCALITY: Female ex male Prosciurillus leucomus (USNM 218077; Rodentia , Sciuridae , Nannosciurinae, Nannosciurini, Hyosciurina) collected by H.C. Raven at 200 m at Labuan Sore (00 ° 379S, 120 ° 039E; see gazetteer and fig. 11), Propensi Sulawesi Tengah, Indonesia on 1 December, 1916. The holotype is deposited in the USNM.

REFERRED SPECIMENS: In addition to the holotype female, two more female specimens, one from the same host (USNM 218077) as the holotype, the other ex male Prosciurillus leucomus (AMNH 196566) collected by G. Heinrich at 900 m at Rurukan (01 ° 219N, 124 ° 529E; see gazetteer and fig. 11), Propensi Sulawesi Utara, Indonesia on 22 January 1931 .

DISTRIBUTION: Hoplopleura leucomus is known only from Prosciurillus leucomus , which is recorded from voucher hosts collected at 200 and 900 m. This tree squirrel occurs throughout lowland and montane altitudes in the northern peninsula of Sulawesi and on Pulau Lembeh off the northeastern coast (see fig. 11 and table 4).

ETYMOLOGY: Named for the specific epithet of the host species.

DIAGNOSIS: Females of Hoplopleura leucomus can be distinguished from females of all other species of Hoplopleura using a combination of the following characters of the female genitalia and associated structures, which are all shown in figure 48E: (1) the distinct shape of the subgenital plate which appears as two laterally elongate plates that are connected medially; (2) the presence of two long setae laterally on each side of the upper section of the subgenital plate together with four central setae (two lateral setae of medium size, two small central setae) in the anterior portion of the lower section of the subgenital plate; (3) the elongate shape and setation (especially the more recessed insertion of the middle of the three setae) of the gonopods VIII. Females of Hoplopleura leucomus have morphological similarities to females of the other species of Hoplopleura described from Sulawesi squirrels in this report in that the subgenital plates all show tendencies toward being separated into two major sections, one anterior and one posterior. In some species, the plate sections are joined medially whereas in others the plates are completely separated. This subgenital plate conformation is rare in females of other species of Hoplopleura regardless of their host(s) or geographic distribution. Although females of all eight of the species of Hoplopleura we describe from Sulawesi squirrels in this report show this morphological trend, a glance at the plates of the females for each of the eight species will immediately show that the species are all very easily separated using only the distinctive morphology and setation of this structure.

DESCRIPTION: Female (fig. 48A–E). Length of holotype 1.22 mm (mean for series 1.30; range 1.21–1.47, N 5 3). Head, thorax, and abdomen well sclerotized.

Head. Longer than wide with broadly rounded anterior apex; 2 SuHS, 4 DMHS, 1 DAnCHS, 1 SpAtHS, 3–4 AnMHS, and 1 VPHS on each side; DPHS fairly long, extending to mesothoracic spiracle, with 1 DAcHS medial to DPHS on each side. Antennae. 5-segmented with basal segment much wider than second segment, wider than long; second segment elongate.

Thorax. Slightly broader than long; thoracic sternal plate (fig. 48B) with broadly rounded anterior apex, tapering, broadly rounded posterior apex, and broadly round- ed lateral margins; mesothoracic spiracle moderate in size (0.019 mm in diameter); DPTS moderate in length (0.12 mm) almost extending to mid region of level of paratergal plate I; no DMsS evident. Legs. Fore and mid coxae subtriangular; forelegs small each with narrow acuminate claw; hindlegs robust each with broad acuminate claw; midlegs intermediate in size between fore and hind legs.

Abdomen. Wider than thorax; 15 plates dorsally comprising three narrow plates on each of segments 4–7, two narrow plates on segment 8 and one broad, curved plate posteriorly; no dorsal plates on segments 1– 3; one broad plate per segment ventrally on each of segments 2 and 3; three narrow plates per segment ventrally on each of segments 4– 7, and one narrow plate on segment 8; first row of DCAS with two long, thin setae, second and third rows each with four long, thin DCAS, followed by three rows of long, slightly stouter TeAS each with 8–10 TeAS and then by 11 rows of 8–10 dagger-shaped TeAS, and one row of six long, thin TeAS; 10 rows of 1–2 DLAS on each side between segments 4–8; first ventral plate without setae; other ventral plates anterior to subgenital plate each with 8–10 StAS; ventral plates 2 and 3 each articulating with corresponding paratergal plates; ventral plate 2 with three stout lateral StAS on one side (as shown in fig. 48A; two on the other side) and three narrow medial StAS; ventral plate 3 with two robust lateral StAS on each side and three narrow medial StAS; ventral plates 4– 16 all with dagger-shaped StAS. Paratergal plates (fig. 48C, D, showing variation) present on segments 1–8: plate II with one long apical seta and one of intermediate length; plate III with two apical setae of intermediate length; plates IV–VI each with one apical seta of intermediate length and the other shorter in length (especially in specimens from Labuan Sore in central Sulawesi as shown in fig. 48C); plates VII and VIII each with two long apical setae; plates I–VI subtriangular; plates II–VI each with both apical angles produced into points; plates III–VII each with moderate size spiracle.

Genitalia (fig. 48E). Subgenital plate with deep lateral indentation on each side and appearance of two separate plates joined medially; two long lateral setae on each anterior arm of subgenital plate; one seta of intermediate length on each side on posterior demarcation of area where two plates appear to be joined, and two small medial setae; gonopods VIII with three apical setae with the middle of these three setae being recessed laterally from plate margin and posterior seta slightly larger than other two setae; gonopod IX with one stout seta; vulvar fimbriae distinct.

REMARKS: Often, male genitalia have important distinguishing characters that delineate different species of congeneric sucking lice. Unfortunately, no males of H. leucomus were available for study. Nevertheless, we decided to describe this species based only on female specimens for two reasons. First, as discussed above, the subgenital plate and its associated setae are highly distinctive for this new species as is the subgenital plate morphology for each of the squirrel-associated lice we describe in this report. Secondly, Hoplopleura leucomus likely cospeciated with its host, Prosciurillus leucomus ; that host along with each of the other seven Sulawesi squirrel species from which we obtained lice has a unique species of louse. The slight differences we note between the lengths of apical setae on some of the paratergal plates (see fig. 48C, D) on lice collected from Prosciurillus leucomus from different geographic regions are minor and reflect variation within the limits of a single species. The distinctive female genitalic structures, especially of the subgenital plate and its associated setae, are taxonomically more important and are the same in all three specimens we examined regardless of geographic origin. Obviously, it will be important to collect and describe the male of this species and to compare the morphology of lice from P. leucomus from different localities if more specimens become available. Molecular analyses using fresh louse samples would also be desirable.