Thyreus garouensis Engel, 2014

Engel, Michael S., 2014, A new species of Thyreus from northern Cameroon (Hymenoptera: Apidae), Journal of Melittology 2014 (42), pp. 1-8 : 2-7

Thyreus garouensis Engel , new species

ZooBank: urn:lsid:zoobank.org:act:30B0A40B-C8FB-44E3-BED9-21206D12AB5D

( Figs. 1‒4 )

DIAGNOSIS: The new species can be recognized by the following combination of characters: maxillary palpus with two minute palpomeres; a slightly medioapically produced sternum V with a short medial carina; the form of the mesoscutellum ( Fig. 4 ); and pattern of whitish and palid pastel blue pubescence as described below (vide infra).

DESCRIPTION: ♀: Total body length 10.6 mm; forewing length 8.8 mm. Head wider than long, length 2.6 mm, width 3.3 mm; maxillary palpus with two minute palpomeres; upper interorbital distance 1.8 mm; lower interorbital distance 1.5 mm. Intertegular distance 2.8 mm; mesoscutellar posterior margin with broad concavity, concavity not distinctly sinuate, posterior margin from median notch to posterolateral angle relatively straight (only faintly arched lateral to median notch), depth of concavity about one-half length of posterior margin from median notch to posterolateral angle; posterolateral angles almost orthogonal, not projected as spine. Pygidial plate relatively narrow, margins straight and converging apically, apex narrowly rounded, surface imbricate and impunctate, apical half with slightly raised medial ridge and apically with slightly swollen surface; metasomal sternum V slightly produced medioapically, with short, longitudinal, median carina apically and extending onto medioapically produced margin.

Labrum smooth with scattered, irregularly-sized punctures, such punctures separated by a puncture width or less except medially more sparse and laterally slightly more dense, basally surface weakly swollen paramedially, surface apically with short, triangular point; clypeus and supraclypeal area with small contiguous punctures, integument between (where evident) smooth; face as on clypeus except punctures becoming slightly more spaced, separated by less than a puncture width; punctures on vertex and gena similar to those on upper frons, separated by a puncture width or less, integument between smooth to faintly imbricate. Pronotum with coarse, shallow, nearly contiguous punctures; mesoscutum with well-defined punctures separated by a puncture width or less, integument between punctures smooth and shining; mesoscutellum, including axilla, with punctures as on mesoscutum; pleura with coarse, nearly contiguous punctures, integument between punctures (where evident) smooth and shining, such punctures becoming more widely spaced ventrally; lateral and posterior surfaces of propodeum with coarse, nearly contiguous punctures. Metasoma with small punctures separated by a puncture width or less, integument between faintly imbricate, narrow imbricate and impunctate zones along apical margins of terga except tergum V with broad, slightly depressed, imbricate and impunctate zone in apical half; sterna with punctures separated by more than a puncture width medially, becoming gradually more closely spaced laterally until contiguous, integument between finely imbricate to imbricate, apical margins impunctate and imbricate.

Integument black except labrum, mandible, labiomaxillary complex, legs, and portions of metasomal sterna and tergum VI dark brown, nearly black in some places. Wing membranes hyaline and infumate except white just apical to third submarginal and second medial cells and some small spots apically within these cells ( Fig. 1 ); veins dark brown to black.

Pubescence generally dark fuscous to black over entire body except in presence of plumose white or pallid pastel blue setae as noted below. Clypeus, supraclypeal area, and face except for central and upper frons, largely obscured by dense pubescence ( Fig. 2 ), clypeus and supraclypeal area with short, plumose, pallid blue setae as well as longer more whitish setae; face with some shorter, pallid blue setae but with longer whitish setae more prominent, such setae becoming more sparse by paraocular area and in central and upper frons and ocellar area ( Figs. 2 , 3 ); vertex, occiput, and gena with longer, more erect, whitish setae along on face although still some with pallid pastel blue coloration ( Figs. 1–4 ); postgena with long, whitish setae more sparse than on gena. Mesosoma with pallid pastel blue patches (blue coloration subtle and can appear more white depending on intensity of lighting and orientation, or at times intermingled with white setae and intensity varies as a degree of predominance of one setal color form versus the other) as follows (following annotation of Lieftinck, 1968, and refined by Straka & Engel, 2012): lpn (lateral pronotal patch) present and prominent, separated medially by about apical width of ms (median mesoscutal patch); deps (dorsal mesepisternal patch) and hypm (hypoepimeral area patch) present and prominent, former occupying entire upper half of mesepisternum below scrobal groove, lateral covering entire hypoepiermal area ( Fig. 1 ), deps (dorsal mesepisternal patch) and hypm (hypoepimeral area patch) separated by thin band of black along scrobal groove, otherwise effectively contiguous ( Fig. 1 ); veps (ventral mesepisternal patch) ill-defined, composed of scattered whitish to pallid blue setae ( Fig. 1 ); als (anterolateral mesoscutal) present but thin, not extending as far medially as lpn (lateral pronotal patch) ( Fig. 3 ); ms (median mesoscutal patch) present and prominent ( Fig. 3 ), extending posteriorly to about midlength of mls (mediolateral mesoscutal patch); mls (mediolateral mesoscutal patch) present, well defined, nearly as large as pls (posterolateral mesoscutal patch) ( Figs. 3, 4 ); plsa (anterior posterolateral mesoscutal patch) present from anterior of tegula to near border with axilla ( Figs. 3, 4 ), thinly separated by black from axilla, not but almost meeting pls (posterolateral mesoscutal patch) posteriorly; t (tegular patch) present and prominent posteriorly on tegula ( Figs. 3, 4 ), very small, secondary patch at anterior border of tegula ( Fig. 3 ); pls (posterolateral mesoscutal patch) present, large and prominent ( Figs. 3, 4 ), separated medially by slightly more than width, not extending laterally to meet plsa (anterior posterolateral mesoscutal patch). Mesoscutellum with dense patch of long, plumose, white setae extending posteriorly from undersurface of mesoscutellum medially ( Fig. 4 ), patch not reaching to posterolateral corners; setal patches ps (parascutellar patch) and s (mesoscutellar patch) absent, without apical, medioscutellar patch of whitish setae, thus mesoscutellar dorsal surface entirely black ( Fig. 4 ); lp (lateral propodeal patch) present around propodeal spiracle. Legs with patches present on outer surface of protibia ( Fig. 1 ); small patch apically on posterior surface of profemur; few pallid blue setae intermixed on outer surface of probasitarsus; patch on upper three-quarters of outer surface of mesotibia ( Fig. 1 ); on apical half of posterior surface of mesofemur; few pallid blue setae intermixed on outer surface of mesobasitarsus; patch on upper half of outer surface of metatibia ( Fig. 1 ); pallid blue setae scattered on outer surface of metabasitarsus ( Fig. 1 ). Metasomal terga with prominent patches of appressed, plumose pallid blue setae (pale blue pastel coloration subtle and under strong light can bleach out and appear almost white) ( Figs. 3, 4 ) as follows: first metasomal tergum with large, mostly L-shaped patches laterally, anteriorly patches only slightly extended medially (and thus not truly Cshaped), posteriorly extended more medially (giving L-shape), but not approaching midline, separation between patches about as large as posterior length of patch ( Figs. 3, 4 ); second metasomal tergum with lateral patch largely transverse, slightly extended anteriorly at extreme lateral margin ( Fig. 4 ), patch wider than twice length; third and fourth metasomal terga with similar lateral, transverse patches, third patch wider than twice length, fourth about twice as wide as long, neither with anterior extensions laterally; fifth tergum with small lateral patches except white setae more dominant relative to pallid blue setae; sixth tergum without patches; second and third sterna with thin, lateral, transverse patches of pallid blue setae ( Fig. 1 ), patch of second sternum more prominent, that of third poorly defined; fourth sternum with a couple of white to pallid blue setae in similar lateral position to patches of second and third sterna but not composed into a distinct patch.

♂: Unknown.

HOLOTYPE: ♀, Cameroun [République du Cameroun]: rég. du Nord [Région du Nord] Garoua . 17 XI 1979 [17 November 1979]. G. Popov ( SEMC).

PARATYPES: 1♀, same data as holotype ( SEMC).

ETYMOLOGY: The specific epithet is based on the type locality, a savanna area in the Région du Nord ( North Province ) of Cameroon.

COMMENTS: In Eardley’s (1991) key to the sub-Saharan species of Thyreus , T. garouensis will run to couplet 21 and since it fails to agree with T. pictus (Smith) , will run out to T. scotaspis (Vachal) , more on the lack of features rather than any positive evidence to assign it. Thyreus scotaspis is one of those species lacking a thoroughly modern, detailed description but there are sufficiently understood details to exclude this as a possibility for the present taxon. Thyreus garouensis may be distinguished from T. scotaspis by the entire clypeus and lower half of supraclypeal area densely clothed in whitish and pallid blue plumose setae ( Fig. 2 ) (clypeus medially and entire supraclypeal area black in T. scotaspis ); the plsa and pls coming close to contact (widely separated in T. scotaspis ); the hypm very narrowly divided from deps by black setae along scrobal groove (these widely divided by black setae in area of scrobal groove in T. scotaspis ); mesoscutellar concavity broad, its depth about one-half distance from notch to posterolateral angle (concavity deeper, more distinctly V-shaped, its depth about as long as distance from notch to posterolateral angle in T. scotaspis ), and the more extensively white and pallid blue setae of the gena, postgena, and occiput (posteriorly more black in T. scotaspis ). Modified couplets for females in Eardley’s (1991) key to accommodate T. garouensis are (male portions are excluded as the male remains unknown for T. garouensis ):

21. Dorsal surface of mesoscutellum partly black, posteromedially with pale blue setal patch .............................................................................. T. pictus (Smith)

—. Dorsal surface of mesoscutellum entirely black ............................................. 21a

21a. Clypeus entirely and supraclypeal area largely covered in whitish and pallid blue plumose setae ( Fig. 2 ); plsa and pls nearly contacting ( Figs. 3, 4 ); hypm and deps barely separated by thin line of black along scrobal groove ( Fig. 1 ); mesoscutellar concavity broad, depth about one-half distance from median notch to posterolateral angle ( Fig. 4 ) .................................... T. garouensis , n. sp.

—. Clypeus medially and supraclypeal area entirely black; plsa and pls widely separated; hypm and deps broadly divided by black across region of scrobal groove; mesoscutellar concavity deep, depth subequal to distance from median notch to posterolateral angle ......................................... T. scotaspis (Vachal)

If one were to ignore the lack of a distinctly sinuate margin to the mesoscutellum and the fact that the pubescence patterns of the first tergum do not match the second part of Eardley’s (1991) couplet 20, then the new species could be confused with T. vachali or even T. brachyaspis (Cockerell) , the latter of which is confined to southern Africa. Neither of these species approximate to T. garouensis in the form of the mesoscutellum or patterns of coloration ( Eardley, 1991).

Figures

Figures 1–2. Female of Thyreus garouensis, new species, from northern Cameroon. 1. Lateral habitus. 2. Facial view.

Figures 3–4. Dorsal views of female of Thyreus garouensis, new species, from northern Cameroon. 3. Direct dorsal view on mesosoma for view of setal patch pattern, with metasoma slightly angled into the background. 4. Direct dorsal view on metasoma for view of setal patch pattern, with mesosoma slightly angled away.