Brachymelecta haitensis ( Michener, 1948 )

Onuferko, Thomas M., Packer, Laurence & Genaro, Julio A., 2021, Brachymelecta Linsley, 1939, previously the rarest North American bee genus, was described from an aberrant specimen and is the senior synonym for Xeromelecta Linsley, 1939, European Journal of Taxonomy 754, pp. 1-51 : 25-29

Brachymelecta haitensis ( Michener, 1948)

Figs 4A , 6C , 9A , 10–11, 12B, 17

Melecta haitensis Michener, 1948: 16 (♂).

Proposed common name

Hispaniolan digger-cuckoo bee.

Diagnosis

Unique within the genus to B. haitensis is that the T1–T3 fasciae of the male are complete ( Fig. 9A ). In all other species of Brachymelecta , at least the T2 and T3 fasciae (if present) (as well as any fasciae on the succeeding terga) are interrupted medially in males ( Figs 8A–C , 9B ) as well as females, except in aberrant specimens in which the metasoma is entirely covered in pale tomentum (see Fig. 7A–B ). The following morphological features in combination (excluding any that are specific to the opposite sex of the one being diagnosed) can be used to tell B. haitensis apart from all other Brachymelecta except B. tibialis , a Puerto Rican/ U.S. Virgin Islands species: the mesoscutum and mesoscutellum both have well-defined bands of pale hairs along the entire midline that connect and thus give the appearance of a single band ( Figs 10B, D , 11 ); the mesoscutellum sometimes also has pale hairs laterally but the pubescence is otherwise dark brown or black, sparse, and does not obscure the underlying integument ( Fig. 10D ); and each mesotibia of the female dorsally has a large glabrous area between a submedial band of off-white to pale yellow hairs (nearer the base than apex) and a band on the apical margin ( Fig. 10A ). Apart from the difference in the T1–T3 fasciae of the male, B. haitensis may be separated from B. tibialis as follows. Whereas in B. tibialis the T1–T3 fasciae of the female are widely interrupted medially and the lighter hairs covering the head, mesosoma, and metasoma are off-white, in B. haitensis the T1–T3 apical fasciae of the female are only narrowly interrupted medially and the lighter hairs covering the head, mesosoma, and metasoma are pale yellow. Brachymelecta haitensis is the only species in the genus known to occur in Hispaniola, where it is endemic.

Material examined

Holotype

HAITI • ♂; Ouest, Port-au-Prince; G.N. Wolcott leg.; USNM 534228 .

DNA barcoded material

Available. BIN: BOLD:AEH8436. Specimen examined and sequenced:

DOMINICAN REPUBLIC • 1 ♂; Indepencencia, Sierra de Bahoruco, Caseta #2; 23 Nov. 2008; J.A. Genaro leg.; BOLD sample ID: CMNTO_037; JAG .

Non-barcoded material

DOMINICAN REPUBLIC • 2 ♂♂; Indepencencia, La Descubierta , Lago Enriquillo , Sierra de Neiba ; Nov. 2006; J.A. Genaro leg.; JAG • 1 ♀, 1 ♂; same collection data as for preceding; PCYU • 1 ♀; La Vega, Los Tablones, La Laguna , Parque Nacional José Armando Bermúdez ; 30 Jun. 2004; D. Pérez leg.; USNM RD-251 .

Redescription

Male

MEASUREMENTS. Length 10.3 mm; ITW 2.4 mm; head length 2.6 mm; head width 2.9 mm; fore wing length 8.6 mm.

INTEGUMENT COLORATION. Dark brown to black except as follows. Mandible with apical third reddish brown (golden yellow in some non-type specimens). Mandible with middle third, labrum, mesoscutellum, metanotum, and legs, excluding dark brown coxae and tibial spurs (black in non-type specimens), brownish orange (reddish brown to reddish orange in multiple non-type specimens). Tegula amber. Fore wing dusky subhyaline throughout except around third submarginal crossvein and second recurrent vein, where hyaline (all wings badly damaged/stained in holotype; described from non-type specimens). Hind wing dusky subhyaline to hyaline. Much of antenna and metasoma reddish brown in holotype, possibly due to discoloration/fading; dark brown to black in non-type specimens.

PUBESCENCE. Badly matted in holotype (apparently due to prior wetting); described from non-type specimens. Face with hairs densest around antennal socket, predominantly off-white/pale yellow but dark brown/gray above antennal socket and in lower paraocular area. Clypeus with upper half densely hairy; lower half nearly bare. Upper paraocular and frontal areas and vertexal area (except along preoccipital ridge and margin of compound eye) mostly exposed. Head with dense, erect hairs along preoccipital ridge off-white/pale yellow except for pair of dark brown/gray patches, each behind lateral ocellus, separated by small band of off-white/pale yellow hairs along midline between median ocellus and preoccipital ridge, seemingly continuous with band of pale hairs along midline of mesoscutum. Genal beard hairs predominantly off-white/pale yellow. Mesoscutum sparsely hairy except densely hairy anteriorly and along margins, with hairs short, appressed, and predominantly dark brown/gray except for small patch of pale yellow hairs on each side along anterior margin between midline and pronotal lobe, pair of central spots of pale yellow hairs and narrow band extending posteriorly from each toward axilla, well-defined band of pale yellow hairs along midline, and pale yellow hairs along margins. Axilla with conspicuous patch of black hairs. Mesoscutellum with well-defined band of pale yellow hairs along midline, seemingly continuous with band of pale hairs along midline of mesoscutum, and small patch of pale yellow hairs laterally but with pubescence otherwise dark brown or black and sparse, not obscuring underlying integument. Metanotum with short, appressed off-white to dark brown hairs. Propodeum with erect, predominantly pale yellow hairs. Mesopleuron sparsely hairy, but with (off-white/pale yellow) hairs moderately dense ventrally as well as between two sparsely hairy circular patches (one beneath base of fore wing (hypoepimeral area), a larger one occupying much of ventrolateral half of mesopleuron). Legs, from coxae to tarsi, with appressed and erect off-white to pale yellow hairs, ventrally with golden-yellow hairs. Profemur with posteroventral fringe of dense, off-white hairs. Protibia with two bands or spots of short, appressed off-white hairs, one in basal half and one on apical margin. Mesotibia with patch of very dense short, appressed off-white/pale yellow hairs, occupying nearly entire dorsal surface. Metatibia with patch of sparser off-white/pale yellow hairs in apical two-thirds. T1–T3 with well-defined complete apical fasciae, those of T1 and T3 each with lobe-like anterolateral extension on each side with erect among appressed pale yellow hairs, that of T2 with pair of anterolateral extensions on each side. T3 with fascia laterally removed from apical margin, narrowed or interrupted mesad each anterolateral extension. T4–T6 without fasciae, although T4 with few sparsely scattered pale hairs present on apical impressed area. Exposed metasomal sterna mainly with short, appressed off-white hairs.

SURFACE SCULPTURE. Labrum and clypeus with punctures equally dense (most i≤1d). Integument lateral to lateral ocellus punctate. Mesoscutum and mesoscutellum with fine punctures, not much coarser than those of metasomal terga. Mesoscutum and mesoscutellum with punctures equally dense (most i<1d) and similar in size. Mesopleuron with denser (most i<1d) punctures in upper half than ventrolateral half (many i=1–2d), interspaces well-defined and somewhat dull due to tessellate surface microsculpture. Discs of metasomal terga with punctures very fine, dense (i≈1d), interspaces dull due to tessellate surface microsculpture (difficult to see in holotype because integument obscured by badly matted pubescence; described from non-type specimens).

STRUCTURE. Mandible tridentate, with small inner tooth approximately ⅓ length of mandible from base and slightly larger inner tooth approximately ⅓ length of mandible from apex as well as usual large apical tooth (rutellum). Maxillary palpus apparently with one palpomere (three according to Michener 1948). Scape with greatest length 1.8 × greatest width. F2 nearly as long as wide (L/W ratio = 0.9). Mesoscutellum strongly bigibbous, with pair of long, acute, subparallel spines, directed posteriorly. Lateral surface of propodeum posterior to spiracle with rugose crescent ridge, strongly carinate above and joining anterior lip of spiracle. Fore wing with three submarginal cells. T7 with slight median emargination.

Female

Description as for male except for usual secondary sexual characters and as follows: scape longer, with greatest length 2.1 × greatest width; mesotibia dorsally with large glabrous area between submedial band of off-white to pale yellow hairs (nearer base than apex) and band on apical margin; T1–T3 with fasciae narrowly interrupted medially; T 4 in some specimens with pair of small spots of pale yellow hairs along anterior margin of apical impressed area; T6 with narrow, V-shaped but apically rounded pygidial plate with median longitudinal ridge.

Distribution

Previously known only from Haiti and herein newly reported from the Dominican Republic, this is the only species of Brachymelecta known to occur on the island of Hispaniola ( Fig. 4A ).

Ecology

Host records

Unknown. Given that New World Melectini have been associated only with anthophorine bees (mostly Anthophora ), presumably B. haitensis is a cleptoparasite of one or more of the three species

of Anthophora — A. hilaris , A. hispaniola Brooks, 1999 , and A. tricolor (Fabricius, 1775) — known to occur in Hispaniola (see Brooks 1999).

Floral records Lippia graveolens Kunth (Verbenaceae) ( Fig. 11 ). Images on iNaturalist (https://www.inaturalist.org) show this species visiting Berylsimpsonia B.L.Turner (Asteraceae) (det. by J. Llamacho). One of the

authors of the present study (JAG) has observed males of this species visiting the flowers of Lantana .

Remarks

Michener (2007) indicated that in the Antillean species of Xeromelecta the maxillary palpi have three (or possibly sometimes two) palpomeres. Both B. alayoi and B. haitensis were originally described as having three-segmented maxillary palpi. In the original description of the latter species, Michener (1948) indicated that in the only other Antillean species known at that time ( M. pantalon , later determined to be a junior synonym of X. tibialis ) the maxillary palpi were reportedly two-segmented but noted that the discrepancy was possibly the result of an observational error by Dewitz (1881) as the palpi are minute. In the present study, the maxillary palpus of a male specimen of B. haitensis (BOLD sample ID: CMNTO_037; JAG) was visualized with an SEM, which revealed an enlarged basal portion but no discernible articulations to suggest it has three or even two palpomeres (see Fig. 12 ). The maxillary palpi of two other specimens (the holotype and a non-type female) were also examined, albeit under a dissecting microscope, and similarly in each an enlarged basal portion was clearly evident but separate palpomeres were not.

Brachymelecta haitensis exhibits unusual sexual dimorphism in that in females the T1–T3 apical fasciae are interrupted medially, albeit narrowly, whereas in males the T1–T3 apical fasciae are complete. This difference between the sexes is consistent across the specimens from Hispaniola that were studied. Previously known from a single (male) specimen, the female of B. haitensis is described here for the first time.

Figures

Fig. 4. Species distribution maps.A. Brachymelecta alayoi (Michener, 1988) (yellow circles),B. haitensis (Michener, 1948) (red circles), and B. tibialis (Fabricius, 1793) (blue circles). B. B. californica (Cresson, 1878) (red and blue circles indicate barcoded specimens assigned BINs BOLD:AAC6481 and BOLD:AAC6482, respectively). C. B. interrupta (Cresson, 1872). D. B. larreae (Cockerell, 1900). Known localities based on studied material and literature records are indicated by yellow circles except where indicated otherwise; subnational entities colored in orange indicate known/published provincial/ state records.

Fig. 6A–C (continued on next page). Dissected male S7 (left) and S8 (right), ventral view (with anterior ends oriented toward the top). A. Brachymelecta californica (Cresson, 1878) (photo of Melecta californica paralectotype (ANSP 2292-5)).B. B. californica (photo ofM.? mucida holotype (ANSP 2294) (herein synonymized under B. californica)) (S8 appears to have been damaged/split anteromedially). C. B. haitensis (Michener, 1948) (JAG).

Fig. 9.Metasoma of male, dorsal view.A. Brachymelecta haitensis (Michener, 1948) (JAG).B. B. tibialis (Fabricius, 1793) (UPRM).

Fig. 8. Brachymelecta californica (Cresson, 1878), habitus, dorsal view. A. Male specimen (ANSP) from Nevada (bearing the same ‘Nev’ collection label as the Melecta? mucida holotype) in which both fore wings have two submarginal cells. B. M. californica paralectotype, ♂ (ANSP 2292-7) in which the left fore wing has three submarginal cells and the right has two, with the second submarginal cross vein incomplete. C. M. californica paralectotype, ♂ (ANSP 2292-4) in which the left fore wing has two submarginal cells and the right has three (note that in both fore wings, the second submarginal cross vein (incomplete on the left, complete on the right) originates from the first submarginal cross vein, not Rs as is typical for most bees, including this species). D. Female specimen (BOLD sample ID: CCDB-34570 A03; PCYU) in which the discs of the metasomal terga are (unusually for B. californica) covered in short, pale hairs, sparser than those comprising the apical fasciae.

Fig. 7. Melecta? mucida holotype, ♂ (ANSP 2294) (herein synonymized under B. californica (Cresson, 1878)). A. Habitus, dorsal view (blue arrows indicate apical fasciae of metasomal terga). B. Metasoma, dorsal view (blue arrows indicate apical fasciae of metasomal terga) (pubescence appears to be matted from prior wetting). C. Habitus, lateral view. D. Head, frontal view.

Fig. 10. Brachymelecta haitensis (Michener, 1948). A–B. Female (USNM RD-251). A Habitus, lateral view. B Habitus, dorsal view. C. Male (JAG), habitus, lateral view. D. Female (PCYU), axillae and mesoscutellum, dorsal view.

Fig. 11.FemaleBrachymelecta haitensis (Michener, 1948) taking nectar from flowers of Mexican oregano (Lippia graveolens Kunth (Verbenaceae)) (location: Altamira, Puerto Plata, Dominican Republic). A. Shown with mouthparts extended into corolla. B. Shown with mesoscutellum and metasomal fasciae in view. Images courtesy of L. McDowell Johnson.

Fig. 12. SEM images of maxillary palpus, lateral view, of male. A. Brachymelecta californica (Cresson, 1878) (BOLD sample ID: CCDB-34570 A05; PCYU), which distinctly has four palpomeres. B. B. haitensis (Michener, 1948) (BOLD sample ID: CMNTO_037; JAG), which has no distinct articulations beyond its attachment to the rest of the maxilla and thus one palpomere (blue arrow).