Lasioglossum (Dialictus) amona, Gibbs, 2018

Gibbs, Jason, 2018, Bees of the genus Lasioglossum (Hymenoptera: Halictidae) from Greater Puerto Rico, West Indies, European Journal of Taxonomy 400, pp. 1-57 : 13-16

Lasioglossum (Dialictus) amona sp. nov.

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Figs 4A , 6–8

Diagnosis

Both sexes of L. amona sp. nov. can be recognized by the combination of tegula honey-coloured and oval without extended posterior angle, mesepisternum distinctly punctate, interspaces polished and metasoma brown.The female has a distinct oblique propodeal carina, T2–T3 basolaterally with appressed tomentum and T2–T3 apical impressed areas distinctly, but finely punctate. In size and sculpturing, L. amona sp. nov. is similar to members of the L. parvum species complex, but can be recognized by the unmodified tegula. It is closely allied to L. dispersum sp. nov., but differs in the female by the smoother mesepisternal sculpturing of interspaces, finer mesoscutal punctation, smoother dorsolateral slope and less distinct oblique carina. The male can only be distinguished from those of L. dispersum sp. nov. by the paler green colour and honey-coloured tegula. Lasioglossum genaroi sp. nov. is related, but has rugose to reticulate-rugose mesepisternal sculpturing and typically a larger body size, which in females is significantly larger on average, and a darker blue colour.

Etymology

The specific epithet is a noun in apposition taken from the Taíno name for Mona Island.

Material examined

Holotype

PUERTO RICO: ♀, Mona Island , 5 Apr. 1944, J.A. Ramos leg. ( NMNH). [Original label: Mona Island, 5 – Apr. 1944 // J.A. Ramos collector // HOLOTYPE Lasioglossum (Dialictus) amona .]

Paratypes

PUERTO RICO: Mona Island : 1 ♀, topotypical ( JBWM) ; 1 ♀, 30 May 1963, A. Berrios leg. ( JBWM); 1 ♀, Mona Island , 19–26 Jan. 2001, M.A. Garcia and J. Sustache leg. ( AMNH) ; 2 ♀♀, 4 ♂♂, Ulvero, road above , 11 Nov. 1992, Snelling and Torres leg. ( LACM); 2 ♀♀, 1 ♂, Mona Island , Malaise trap, 28–30 Oct. 1991, R.R. Snelling and J.A. Torres leg. ( LACM) .

Description

Female

MEASUREMENTS. Head length: 1.26–1.34 mm (x = 1.29 mm, n= 8); head width: 1.33–1.47 mm (x= 1.40 mm, n =8); intertegular distance: 0.96–1.08 mm (x = 1.01 mm, n=8).

COLOURATION. Head and mesosoma dull metallic golden green, except as follows. Labrum reddish brown. Mandible brown with red apex. Clypeus distal half dark brown. Antenna dark brown, F2–F10 with ventral surface dark reddish brown. Tegula honey-coloured. Wing membrane hyaline with dark setae, venation and pterostigma honey-coloured. Legs dark brown, except medio- and distitarsi reddish brown, basitarsi infused with reddish bown. Metasomal terga brown, apical areas brownish yellow.

PUBESCENCE. Dull white. Relatively sparse erect setae throughout, without tomentum, except narrow basolateral patches of T2–T3 and basally on T4. T1 with complete fan of appressed setae on anterior surface. T2 without apical fimbriae, T3–T4 with only sparse fine setae on apical impressed areas. Scopa well developed on hind leg and metasomal sterna.

SURFACE SCULPTURE. Face imbricate, punctation moderately coarse, finer on frons. Clypeus punctation sparse (i=1–2.5 pd), surface smooth distally (i=2–3 pd), supraclypeal area with punctures moderately dense (i =1–1.5 pd) and lower paraocular area punctation dense (i ≤pd). Upper paraocular area and frons reticulate-punctate (i <0.5 pd). Ocellocular area densely punctate (i≤ pd). Gena and postgena finely carinulate. Mesoscutum imbricate, punctation dense on lateral and posterior portions (i=1–1.5 pd), sparser anteriorly and medially (i=1–3 pd); mesoscutellum similar, with polished submedial impunctate area. Metanotum imbricate-punctate. Preëpisternum rugulose-reticulate. Hypoepimeral area finely, densely punctate (i <0.5 pd). Mesepisternum below scrobe densely punctate (i≤ pd), interspaces weakly imbricate. Metepisternum dorsal ⅓ rugoso-carinulate, ventral portion imbricate. Metapostnotum with longitudinal carinulae reaching ⅔–¾ distance to posterior margin, carinulae on lateral portions extending to dorsolateral slope, raised posterior margin smooth. Propodeum posterior surfaces polished tessellate, distinct punctures on lateral surface (i=3–5 pd). Metasomal terga polished, finely coriarious on T1 anterior surface and apical impressed areas; punctation very fine throughout, including apical impressed areas (i= 1–2 pd). Metasomal sterna coriarious and finely, sparsely punctate (i= 2–4 pd).

STRUCTURE. Head slightly wider than long (length/width ratio= 0.91–0.94). Eyes weakly convergent below. Clypeus ⅔ below suborbital tangent. Gena narrower than eye. Hypostomal carinae subparallel. Pronotal dorsolateral angle obtuse. Pronotal ridge rounded, interrupted by sulcus. Tegula ovoid. Submarginal cells three (1rs-m present). Distal hamuli arranged 2-1-2. Inner metatibial spur pectinate, with 3–4 branches, proximal branch much longer than width of rachis. Metapostnotum slight depressed, narrowly rounded onto posterior propodeal surface. Propodeum with lateral carina reaching dorsal margin; oblique carina present, delimiting ventral-posterior margin on posterior and lateral margins. T2–T4 impressed areas medially nearly equal to longitudinal length of basal area.

Male

MEASUREMENTS. Head length: 1.23–1.40 mm (x = 1.33 mm, n= 5); head width: 1.28–1.48 mm (x= 1.39 mm, n =5); intertegular distance: 0.91–1.05 mm (x =1.00 mm, n=5).

Similar to female except for typical sex associated characters and as follows.

COLOURATION. Head and mesosoma dull metallic bluish green. Ventral surface of F1–F11 brownish yellow. Tarsi brown to brownish yellow. Metasomal terga dark brown, with reddish brown apical margins.

PUBESCENCE. Face below eye emargination with subappressed tomentum, partially obscuring surface. Metasomal terga without tomentum. Metasomal sterna with sparse, posteriorly directed setae.

SURFACE SCULPTURE. Mesoscutum smoother, punctation slightly sparser. Mesepisternum smooth, shining; punctures deep and distinct. Propodeum lateral surface densely punctate (i =1–1.5 pd). Metasomal terga with apical impressed areas impunctate.

STRUCTURE. Head wider than long (length/width ratio= 0.95–0.96). Eyes convergent below. Ratio of pedicel, F1 and F2= 10:12:26; F2–F11 more than 1.5× as long as wide. Metasomal terga with apical impressed areas medially less than ½ length of basal area.

TERMINALIA. As illustrated in Fig. 4A .

Distribution

This species is apparently endemic to Mona Island ( Fig. 8 ).

Remarks

Lasioglossum amona sp. nov. is very closely related to L. dispersum sp. nov. The differences in microsculpture and structure are suggestive of species-level differences, but it seems probable that these two species share a recent ancestor. Additional study is needed to determine whether the morphological and geographical basis for recognizing L. amona sp. nov. as distinct from L. dispersum sp. nov. is valid.

Figures

Fig. 4. Line drawings of male genital capsules in ventral (left side) and dorsal (right side) views. A. L. amona sp. nov. B. L. dispersum sp. nov. C. L. eickwortellum (Engel, 2001). D. L. enatum sp. nov. E. L. genaroi sp. nov. F. L. gundlachii (Baker, 1906).

Fig. 6. Lasioglossum amona sp. nov., ♀. A. Face. B. Lateral habitus. C. Dorsal habitus. Scale bars = 1 mm.

Fig. 7. Lasioglossum amona sp. nov., ♂. A. Face. B. Lateral habitus. C. Dorsal habitus. Scale bars = 1 mm.

Fig. 8. Distribution map for Lasioglossum amona sp. nov.