Neomacrocoris liberianus, Sites, Robert W., 2015

Sites, Robert W., 2015, A new species, new synonymy, and notes on Neomacrocoris (Heteroptera: Nepomorpha: Naucoridae), Zootaxa 3964 (5), pp. 553-560 : 554-557

Neomacrocoris liberianus NEW SPECIES

Figs. 1–2

Macropterous male. HOLOTYPE, length 10.40 (paratype 10.08); maximum width 6.44 (paratype 6.24). General shape elongate oval, widest across embolia ( Fig. 1 ). Overall dorsal coloration yellowish brown anteriorly with dark scutellum and hemelytra; ventral surface mostly brown; legs, lateral margin of abdomen, and lateral part of propleura yellow.

Head. Length 1.88, maximum width 2.72. Yellow with dark brown punctures, brown associated with punctures coalescent near posterior margin; projecting beyond eyes 13% of head length. Eyes dark brown; approximately twice as long as wide, length/width 1.20/0.58; inner margins shallowly concave, lateral margins rounded; synthlipsis at anterior end, 1.28; vertex with visible posterior margin shallowly convex, meeting posteromedial corner of eye. Labrum yellowish brown, broadly rounded distally, twice as wide as long, width/length = 0.84/0.42. Maxillary plate yellowish brown, darker anteriorly, narrow, elongate, extending ventrally approximately to half length of labrum, bordering sides of rostral base. Labium with three visible segments darkening distally from yellow basal segments to yellowish-brown distal segment, short, extending 0.48 beyond labrum. Antenna short, hirsute, extending slightly beyond lateral margin of eye, relative lengths 6:11:13:8.

Thorax. Pronotum broad, highly convex, brownish yellow; scattered brown punctation throughout, paired brown areas immediately lateral to midline; wide transverse band along posterior margin set off with irregular series of brown, longitudinally elongate markings, otherwise immaculate yellow; maximum width 6.00, length at midline 2.88; posterior margin shallowly concave in middle, rounded laterally; lateral margins evenly convex, convergent anteriorly, distinctly explanate; posterolateral corners rounded; vague rugosity especially evident anteromedially; with scattered pale setae. Scutellum dark reddish brown; punctate; with scattered thin setae; width 4.08, length at midline 2.48; mesoscutum partially exposed behind pronotum with head/pronotum deflexion; lateral margins slightly convex. Hemelytra brown with subtle lighter mottling; punctate; with sparse, elongate, recumbent and erect setae; length 7.04 (chord measurement). Clavus distinct, small yellow markings at commissure. Embolium well delineated, lateral margin convex throughout, convexity stronger in posterior half, anterior 2/3 yellowish laterally, maximum width 0.80, length 3.00. Hemelytra not attaining tip of abdomen (terminal abdominal segments were bent downward in Fig. 1 to enable view of terga in Figs. 2 A, B), half of lateral lobes of abdominal segment VIII exposed; venation not evident, membrane of underlapping wing (left) mostly pruinose. Hindwings well developed. Ventrally, prosternum with mid-ventral carina. Propleuron laterally with extensive yellow, glabrous area extending 1/2 distance to mesal margin; black pruinose area mesad of yellow, glabrous area; propleura widely separated at midline. Mesobasisternum with medial carina with elongate pale brown setae and series of 6–7 ventrally directed protuberances; meso- and metasterna mostly dark brown, pruinose.

Legs. All segments yellow except brown protibia and tarsus, meso- and metacoxae. Profemur with scattered brown spots in posterior 2/3 on ventral and dorsal surfaces; anterior margin with dense pad of elongate, goldenbrown setae. Protibia and tarsus with flattened inner surface, tarsus one-segmented, single claw minute. Middle and hind coxae covered with short, pale brown, recumbent setae. Metasternellum (=metaxyphus) with pronounced transverse and longitudinal carinae, thus resembling head of Phillips screwdriver directed posteroventrad. Meso- and metafemora with posteroventral row of pale, peglike spines becoming obsolete proximally; meso- and metafemora and trochanters with posterior surface with short, pale setae, becoming obsolete near distal end of femora; posterodorsal row with pale, elongate setae. Meso- and metatibiae with rows of stout reddish brown spines, 2 transverse rows of long, stout spines at apex, meso- and metatibiae and tarsi with long, golden brown swimming hairs. Meso- and metapretarsal claws paired, slender, evenly curved, with basal tooth. Leg measurements as follows: foreleg, femur 2.76, tibia 1.88, tarsus 0.40; middle leg, femur 2.68, tibia 2.14, tarsomeres 1–3, 0.16, 0.38, 0.52; hind leg, femur 2.96, tibia 3.52, tarsomeres 1–3 0.32, 0.66, 0.66.

Abdomen. Connexiva III–VIII exposed laterally beyond hemelytra; III–VII each yellow anteriorly, brown posteriorly, VIII entirely yellow; lateral margins smooth, with dense fringe of pale setae; posterolateral angles of II–IV square, V–VII acute. Tergum VII with posterior margin with lobe left of midline roundedly acute, devoid of denticles; lobe right of midline (pseudostrigil) large, directed dextrocaudad, flattened, with concavity in distal 1/3, apex reflexed, with dense mat of denticles on dorsal surface in concavity and immediately proximad ( Figs. 2 A, B). Tergum VIII with lobe left of midline posteromedial corner roundedly right angled; right lobe broad, posteromedial corner rounded, posterolateral corner squared. Ventrally brown except narrow marginal glabrous yellow band; densely covered with short, brown, recumbent setae; mediosternites with elongate, erect, brown setae. Sternum V with posterior margin concave and mediosternite VI displaced asymmetrically to left. Genital operculum evenly rounded.

Genitalia. Pygophore brown, elongate setae generally scattered and with a dense brush posteriorly ( Fig. 2 C). Parameres lacking. Pygophore with sides deflexed to wrap around sides of phallosoma. Phallosoma beyond pygophore gently arcing left, then right before lateroflexing to left apically ( Fig. 2 C); sclerotized vesica and membranous endosoma distad of phallosoma.

Female. Unknown.

Diagnosis. The structure of the phallosoma and pseudostrigil of N. liberianus are unique among known congeners and are the most obvious diagnostic attributes. Specifically, the pseudostrigil is mostly flattened and the mat of denticles is on the dorsal surface. This species keys to couplet 4 in Sites & Mbogho (2012) where it presents characteristics of both halves of the couplet. The body is longer than 10 mm; however, the width/length ratio is 0.615. Double keying from couplet 4 leads to Neomacrocoris karimii Poisson or to couplet 14. It can be distinguished from N. karimii of East Africa by the narrower body and phallosoma and pseudostrigil structure. At couplet 14, the condition of the phallosoma is distinct to the point that this species no longer keys satisfactorily.

Discussion. The holotype specimen is from Liberia and was found among identified specimens of Limnocoris pauper Montandon in the USNM. The paratype is from Sierra Leone and was one of three specimens from different African localities in the MNHN that were all identified by Montandon as Pseudambrysus angusticeps (Haglund), now in the genus Neomacrocoris ( Montandon 1913). I determined the other two specimens to be N. handlirschi (Montandon), and they were from the Congo and Mpala, Tanganyika. N. liberianus is the westernmost known species of Neomacrocoris. An unidentified female specimen of Neomacrocoris from Sierra Leone is in the Royal Museum of Central Africa in Tervuren, Belgium ( Sites & Mbogho 2012), but it is unknown if that female is conspecific with N. liberianus .

I considered the possibility that this new species could be N. angusticeps based on the nearly identical overall body size as reported in the original description ( Haglund 1895) and that both occur in western Africa. The type specimen of N. angusticeps is a male from Cameroon and has been missing since the 1930s from the Naturhistoriska Riksmuseum in Stockholm ( Poisson 1948, Sites & Mbogho 2012). I searched more than 20 major museums in Africa, Europe, and America that would be expected to hold specimens of Neomacrocoris and was unable to locate the type. Therefore, a current concept for this species is not possible because the original description is only seven lines in length; as such, N. angusticeps is a nomen dubium. Montandon evidently examined the type of N. angusticeps within two years after it was described and later compared it to other species of African Naucoridae . Although the normally astute Montandon identified the paratype designated here as N. angusticeps, he also identified two specimens of N. handlirschi, which also are in the MNHN, as N. angusticeps. Montandon apparently did not consider the genitalic structure of naucorids but instead based his species concepts on more readily apparent features. As such, performing identifications on specimens of Neomacrocoris by Montandon was rendered tenuous and difficult at best because male structures are necessary ( Sites & Mbogho 2012). The structure of the phallosomas and pseudostrigils of N. liberianus and N. handlirschi are strikingly distinct.

Etymology. The species is named for the country from which the holotype was collected. Repositories. The holotype is housed in the United States National Museum of Natural History and the only paratype is in the Muséum National d'Histoire Naturelle—Paris.

Material examined. HOLOTYPE: LIBERIA: Reputa, WM Mann / Smithsonian Firestone Exp, 1940 ( USNM, ♂). Paratype: SIERRA LEONE / Museum Paris, coll. G. Fallou 259-95 / Pseudambrysus angusticeps Hagl., Montand. det. 1897 ( MNHN, 1♂).

Figures

FIGURE 1. Neomacrocoris liberianus n. sp. HOLOTYPE dorsal habitus. Only connexiva III – V and part of VI visible because terminal abdominal segments were bent downward to enable view of structures in Figs. 2 A, B.

FIGURE 2. Diagnostic structures of male N. liberianus n. sp. (A) Terminal abdominal terga, ps = pseudostrigil. (B) medial and lateral lobes of 7 th tergum. (C) pygophore with aedeagus, size bar = 0.5 mm.