Lasioglossum (Dialictus) stictaspis ( Sandhouse, 1923 )

Gardner, Joel & Gibbs, Jason, 2023, Revision of the Nearctic species of the Lasioglossum (Dialictus) gemmatum species complex (Hymenoptera: Halictidae), European Journal of Taxonomy 858 (1), pp. 1-222 : 161-170

Lasioglossum (Dialictus) stictaspis ( Sandhouse, 1923)

Figs 60– 66 , 76O , 81C , 89B , 91A , 100B , 111B , 112B , 114B

Dialictus stictaspis Sandhouse, 1923: 195 (holotype, ♂, deposited in USNM, examined).

Halictus (Chloralictus) albuquerquensis Michener, 1937: 316 (holotype, ♀, deposited in CAS, examined).

Lasioglossum (Dialictus) stictaspis – Michener 1951: 1119 (catalogue).

Lasioglossum (Chloralictus) albuquerquense – Michener 1951: 1112 (catalogue).

Dialictus stictaspis – Hurd 1979: 1971 (catalogue). — Moure & Hurd 1987: 131 (catalogue).

Dialictus albuquerquensis – Hurd 1979: 1964 (catalogue). — Moure & Hurd 1987: 89 (catalogue).

Diagnosis

See the diagnosis for the L. stictaspis species complex and the diagnosis for L. paululum . Females of L. stictaspis s. str., described from New Mexico, have the tegula relatively large (reaching and sometimes slightly exceeding posterior margin of mesoscutum in dorsal view), with inner posterior margin weakly concave, and densely punctate (IS ≤ 1 PD); metapostnotum dull, tessellate to finely reticulate, and usually with fine subparallel rugae; mesepisternum shiny (sometimes with weak microsculpture) and densely punctate (IS <1 PD); mesoscutum dull and coarsely punctate (2–3 punctures between posterior end of parapsidal line and/or lateral edge of mesoscutum and some IS = 1–2 PD between parapsidal lines); T1–T2 discs finely and moderately sparsely punctate (IS = 1–3 PD) and apical rims impunctate; T3 with dense subapical band of tomentum (often medially interrupted); face short (length/width ratio ≤0.83) and gena narrower than eye in lateral view.

Females of L. stictaspis s. str. are most similar to those of L. angelicum sp. nov., L. diabolicum sp. nov., L. ellisiae , L. gaudiale , and L. pseudotegulare . Females of L. angelicum and L. pseudotegulare have the T1–T2 discs more deeply and densely punctate (IS = 1–2 PD) with some punctures often extending onto apical rims. In addition, females of L. angelicum have the metapostnotum shiny with strong anastomosing rugae, and females of L. pseudotegulare have the face slightly longer (length/width ratio usually>0.83). Females of L. ellisiae have the tegula slightly smaller (not exceeding posterior margin of mesoscutum in dorsal view) and usually more sparsely punctate (up to IS = 1–3 PD), metapostnotum with strong, coarse rugae and basal half shiny, and T3 usually without subapical tomentum (rarely with a sparse, broadly interrupted band). Females of L. gaudiale have the metapostnotum with strong, coarse rugae and basal half shiny, gena about as wide as eye in lateral view, and T3 without subapical tomentum.

Males of L. stictaspis s. str. have the tegula densely punctate (IS ≤ 1 PD), relatively large (slightly exceeding posterior margin of mesoscutum in dorsal view), and inner posterior margin concave, with a small rounded posterior projection about 0.5 lateral OD in size; metapostnotum tessellate to finely reticulate with shallow subparallel rugae; mesepisternum densely punctate (IS <1 PD); mesoscutum coarsely and moderately densely punctate (IS = 1–2 PD); disc of T2 with punctures deep, distinct, and usually dense (IS ≤ 1 PD); and T1–T2 apical rims impunctate.

Males of L. stictaspis s. str. are most similar to those of L. angelicum sp. nov., L. diabolicum sp. nov., L. ellisiae , and L. pseudotegulare . Males of L. angelicum and L. pseudotegulare have the T1–T2 apical rims punctate; in addition, males of L. pseudotegulare have the T2 disc even more densely punctate medially(IS <1 PD). Males of L. diabolicum and L. ellisiae have the tegula slightly smaller (not exceeding posterior margin of mesoscutum in dorsal view) with inner posterior margin straight or sinuous and a blunt posterior angle or point narrower than 0.5 lateral OD, and usually more sparsely punctate in part (IS ≥1 PD); in addition, males of L. ellisiae have the mesoscutum more uniformly and densely punctate (IS ≤1 PD).

Lasioglossum stictaspis s. lat. is highly variable and a large number of specimens, especially those from south or west of New Mexico, may lack one or more of the above diagnostic characters, making them very difficult to separate from similar species.

Etymology

Sandhouse (1923) formed the specific epithet ʻ stictaspis ʼ from the Greek adjective ʻ stiktos ʼ (punctured, spotted) and the noun ʻ aspis ʼ (shield). It likely refers to the punctured tegula of this species.

Range

Western Great Plains and Rio Grande River valley ( L. stictaspis s. str.) and west to California , south throughout Mexico ( L. stictaspis s. lat.).

DNA barcodes

Twenty-four confirmed sequences available, three haplotypes (BOLD process IDs: DLIII224-20, DLIII225-20, DLIII227-20 (haplotype 1); DLIII231-20, NCBEE336-21, NCBEE339-21, NCBEE343-21, NCBEE347-21, NCBEE349-21, NCBEE357-21, NCBEE369-21, NCBEE404-21, NCBEE407-21, NCBEE412-21 (haplotype 2); DLIII124-18, DLIII128-19, DLIII129-19, DLIII130-19, DLIII131-19, DLIII132-19, DLIII135-19, DLIII136-19, NCBEE403-21, SMTPP733-15 (haplotype 3)). Haplotypes 2 and 3 are shared with L. diabolicum sp. nov. Haplotype 3 has some relatively deep divergence and may be possible to split into additional haplotypes. No fixed nucleotide substitutions distinguish all L. stictaspis from all other Nearctic species of the L. gemmatum complex, but one fixed substitution distinguishes haplotype 2: 402(G) (Supp. file 2).

Comments

The species treated by Gardner & Gibbs (2022) as L. stictaspis may include two species, the other one being L. paululum , described from Colorado. See that work for specimen records and range map. Specimens with a duller mesoscutum and ocellocular area, yellowish pubescence, and a slightly weaker T3 subapical band of tomentum match the holotype of L. albuquerquense and are here considered L. stictaspis s. str.. Lasioglossum stictaspis s. lat. ranges south throughout Mexico and west to California . It can have almost any combination of punctation and surface sculpture in any location.

It is likely that L. stictaspis s. lat. comprises multiple species, but correlates between morphological, genetic, and geographic variation cannot be found to support a species hypothesis. One of these may be L. paululum , but additional species from Mexico, Arizona, or California are likely undescribed. More data is needed to clarify limits and relationships between these species.

Figures

Fig. 60. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♀, holotype of L. (D.) albuquerquense Michener, 1937 (CAS). A. Dorsal habitus. B. Lateral habitus. C. Face. Scale bars = 1 mm.

Fig. 61. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♀, Colorado morph (reproduced from Gardner & Gibbs 2022) (UCMC). A. Lateral habitus. B. Dorsal habitus. C. Face. D. Metasoma and propodeum. Scale bars = 1 mm.

Fig. 62. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♀, red-tailed morph. A. Dorsal habitus.B. Lateral habitus. C. Face. D. Metasoma and propodeum. Scale bars = 1 mm.

Fig. 63. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♀, Mexico morph (WRME). A. Dorsal habitus. B. Face. C. Lateral habitus. D. Metasoma. Scale bars = 1 mm.

Fig. 64. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♂, holotype (USNM) (except C, which is a Colorado specimen) (reproduced from Gardner & Gibbs 2022). A. Dorsal habitus. B. Lateral habitus. C. Face. D. Metasoma and propodeum. Scale bars = 1 mm.

Fig. 65. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♂, red-tailed morph. A. Dorsal habitus.B. Lateral habitus. C. Face. D. Metasoma. Scale bars = 1 mm.

Fig. 66. Lasioglossum (D.) stictaspis (Sandhouse, 1923), ♂, Mexico morph (WRME). A. Lateral habitus. B. Dorsal habitus. C. Face. D. Metasoma and propodeum. Scale bars = 1 mm.

Fig. 76. Male genitalia illustrated in dorsal view and positioned such that the gonostylus is parallel to the plane of vision. Retrorse lobes are also illustrated separately to the bottom left of each figure in lateral view, positioned parallel to the plane of vision. A. Lasioglossum (D.) angelicum sp. nov.B. L. (D.) coactus (Cresson, 1872). C. L. (D.) deludens sp. nov. D. L. (D.) diabolicum sp. nov.E. L. (D.) gaudiale (Sandhouse, 1924). F. L. (D.) gloriosum sp. nov. (the retrorse lobe was not visible for illustration). G. L. (D.) helianthi (Cockerell, 1916). H. L. (D.) holzenthali sp. nov. I. L. (D.) indagator sp. nov. J. L. (D.) magnitegula sp. nov. K. L. (D.) perparvum (Ellis, 1914). L. L. (D.) profoundum sp. nov. M. L. (D.) pseudotegulare (Cockerell, 1896). N. L. (D.) rufodeludens sp. nov. This genital capsule was damaged during dissection and some details may be slightly distorted.O. L. (D.) stictaspis (Sandhouse, 1923) (holotype) (reproduced from Gardner & Gibbs 2022). P. L. (D.) tegulariforme (Crawford, 1907) (reproduced from Gardner & Gibbs 2022). Scale bars = 0.25 mm.

Fig. 81. Tegula.A. Lasioglossum profundum sp. nov., ♀, impunctate. B. L. holzenthali sp. nov., ♀, sparsely punctate. C. L. stictaspis (Sandhouse, 1923), ♀, densely punctate. Scale bars = 0.25 mm.

Fig. 89. Face. A. Lasioglossum pseudotegulare (Cockerell, 1896), ♀, slightly longer. B. L. stictaspis (Sandhouse, 1923), ♀, slightly shorter. Scale bars = 0.5 mm.

Fig. 91. T1–T2. A. Lasioglossum stictaspis (Sandhouse, 1923), ♀, dull and finely, somewhat obscurely punctate. B. L. gaudiale (Sandhouse, 1924), ♀, shiny and deeply, distinctly punctate. Scale bars = 0.5 mm.

Fig. 100. Tegulae. A. Lasioglossum diabolicum sp. nov., ♀, with blunt posterior angle (white outline and arrow). B. L. stictaspis (Sandhouse, 1923), ♀, with rounded posterior projection (white outline and arrow). Scale bars = 0.5 mm.

Fig. 111. Face. A. Lasioglossum pseudotegulare (Cockerell, 1896), ♂, slightly longer. B. L. stictaspis (Sandhouse, 1923), ♂, slightly shorter. Scale bars = 1 mm.

Fig. 112. T2.A. Lasioglossum pseudotegulare (Cockerell, 1896), ♂, punctures nearly touching in centre. B. L. stictaspis (Sandhouse, 1923), ♂, punctures not close to touching. Scale bars = 0.5 mm.

Fig. 114. Metapostnotum. A. Lasioglossum gaudiale (Sandhouse, 1924), ♂, shiny with subparallel rugae. B. L. stictaspis (Sandhouse, 1923), ♂, dull with anastomosing rugae. Scale bars = 0.25 mm.