Cresson salitrera Packer, 2021

Packer, Laurence, 2021, A Revision of Cresson Pate (Hymenoptera, Apoidea, Bembicidae) with the description of two new species, Journal of Hymenoptera Research 85, pp. 81-117 : 81

Cresson salitrera Packer sp.nov.

Figs 7 , 21 , 26 , 28 , 30 , 31-33 , 35

Material Examined.

7 ♀, 7♂. • Holotype: ♀; Chile, Region II, km 26.7, Rd. to Aguas Calientes (N. of Mina Vaquillas); -25.375 -69.288; 3350m; 31.x.2015 - 6.ii.2016; L. Packer, blue vane trap; MNHN . Paratypes: Chile • 1 ♀, 2 ♂ paratypes identical data as holotype; PCYU; • 1 ♂; Region II, Rd to Plato de Sopa, km 51.2; -25.379 -69.388; 3040m; 31.x.2015 - 6.ii.2016; L. Packer; yellow pan trap; PCYU; • 3 ♀, 1 ♂; CAS, PCYU; Region II, W. of Mina Vaquillas; -25.370 -69.372; 3130m; 31.x.2015 - 3.ii.2016; L. Packer; white pan trap; PCYU; • 1 ♂; Region II, S. of Cerro dos Hermanos; -25.404 -69.040; 4020m; 17.xi.-7.xii.2013; S. Monckton; PCYU .

Diagnosis.

Most readily distinguished from C. parvispinosus by the reduced areas of red on the metasomal terga (Figs 31-33 ), although usually not as reduced as in C. mariastea ; T1 and T2 are at least black medially, although in one male only narrowly so. In contrast, C. parvispinosus has T1 and T2 entirely red, with at most the extreme base of the anterior declivitous surface of T1 black and T2 with a small apicomedial dark mark. Compared to C. mariastea , the apicomedial spines of T6 in the females are shorter, at most as long as their basal width, but the lateral spines are relatively longer and sharper (compare Figs 26 and 25 ). In both sexes the basal depressed area of T2 is minutely, sparsely punctate in C. salitrera (Fig. 30 ) but more coarsely and densely, i <d, punctate in C. mariastea (Fig. 29 ). The degree of curvature of F11 differs, in C. salitrera the ventral surface is at an angle of ~80° to the longitudinal axis of the flagellum (Fig. 28 ) while this is ~40° in C. mariastea (Fig. 27 ).

Description.

Holotype female (Figs 31-32 )

Dimensions: Body length 7.1 mm, forewing length 5.1 mm, head width 2.18 mm, ITW 1.35 mm.

Colouration: Black, following parts white to pale yellowish: mandible basal one-third (rest red brown), labrum, lateral ¼ of clypeus, narrow club-shaped mark on upper paraocular area adjacent to inner margin of compound eye extending from upper tangent of supra-antennal area almost to dorsal tangent of frontal depression, small spot on genal area above adjacent to posterior margin of compound eye, transverse mark towards side of pronotal collar separated by slightly less than width of the mark, pronotal lobe (margined with black above, red-brown below), mark on scutellum occupying less than lateral one-quarter, posterior extremity of axilla, broadly divided transverse mark on mesopleuron anterior to mesocoxae, outer half of ventral surface of procoxa, outer half of mesocoxa, extreme apex of metacoxa, apicoventral and posterior two-thirds of profemur, anterodorsal surface of all tibiae (mostly pale yellow on pro- and mesotibiae, mostly white on metatibia), probasitarsus anteriorly, mesobasitarsus basal half; transverse subapical bands on T1-T5, entire on T1, T4 and T5, medial interruptions of T2-T3 blackish; narrow subapical bands on S2-S4 interrupted medially and incomplete laterally (replaced by orange-brown). Following parts orange to orange-brown: torulus, scape apicoventrally, most of posterior surface of metatibia (blackish ventrally), all remaining tarsomeres, T1 triangular marking anterior to subapical cream band broadest laterally, T2 lateral three-tenths red except anterior depression; apical tergal depressions pale straw to transparent.

Pubescence: Silver appressed and obscuring, or almost obscuring, underlying integument on lower paraocular area, frontal depressions, genal area adjacent to compound eye, mesopleuron, scutellum posterolateraly, metanotum except anteromedially and dorsolateral portion of propodeum; somewhat less dense on clypeus, pronotal collar, anterior one eighth of mesoscutum, most of horizontal portion of T1; suberect longer whitish setae ~1.2 MOD on most of genal area and mespisternum; erect long whitish setae <~1.7 MOD on upper face; short <0.5 MOD erect pale setae on dorsal surface of mesocosm and T4-T6, similar setae shorter on T1-T3 and metasomal sterna with a few longer setae subapically ≤ 0.7 MOD.

Surface sculpture: Micropunctures absent on face except on vertex, sparse on mesoscutum and scutellum, abundant on metasomal terga, sparse on sterna and dense, i <d on genal area; punctation mostly coarse and dense, almost crowded on face with interspaces raised among linear groups of punctures, appearing almost striate, striae radiating from ocellar area; genal area larger punctures irregularly spaced i = 0.2-4d. Mesoscutum densely punctate i <d except posteriorly on disc i ≤ 2d; scutellum punctures i <d; mesopleuron large punctures i <2d, posteriorly almost impunctate, metapleuron lacking sculpture except for a few short longitudinal carinae posterodorsally; lateral surface of propodeum carinate for posterodorsal two-thirds. Larger punctures of T1 irregularly spaced i <3d, on T2 i <4d except with areas lacking large punctures posteromedially; basal depressed area of T2 with shallow, sparse minute punctures i> 5d; T3 i <3d, T4-T5 i> 2d, T6 i <0.5d; S2 i <2d, S3 i <1.5d, S4 i ≤ d, S5 i <2d, S6 i <d except midline largely impunctate.

Structure: Head almost 1.5 × as wide as long, 89:61; labrum W:L 36:13 apical margin somewhat concave medially; clypeus W:L 62:23, lip less than half as wide as clypeus, 28, distinctly narrower medially than towards sides; supraclypeal area median length approximately one sixth as long as clypeus; AOD almost 1.5 × maximum width of F1 (15:11); supra-antennal area longer than maximum width 30:18, as long as scape; frontal depression extending to ~0.5 MOD below lower tangent of median ocellus above; UOD:LOD:MINOD 71:45:35; IOD = OOD; scape less than twice as long as greatest width (30:17); pedicel shorter than wide 11:13; F1 2.5 × as long as greatest width 25:10; F2 less than twice as long as greatest width 20:11, remaining flagellomeres increasingly shorter from F3 to F9 except F10 16:12; pronotal collar almost half as long medially as MOD, 10:18; admedian line complete, more distinct for anterior half, scutellum with irregular medial line and large shallow depression posteromedially; length of scutellum:metanotum:metapostnotum 41:15:23. T6 triangular, sides forming an angle of ~80°, with four (left) to five acute teeth (right) extending to midlength of side of tergum, two apical teeth short, equal in length to their basal width, 4:4, separated by a distance clearly greater than their length, 7.5. S2-S5 apical depressions ~0.5 MOD, somewhat narrower medially but not abruptly so.

Male (Fig. 33 )

Dimensions: Body length 7.8 mm, forewing length 5.2 mm, head width 2.25 mm, ITW 1.42 mm.

Colouration: Black, following parts white to pale yellowish: mandible basal half (rest red-brown), labrum, clypeus, supraclypeal area, paraocular area completely filling space between antennal socket and eye below, extending narrowly along eye margin above to approximately 1 MOD below lower tangent of medial ocellus, tiny spot on genal area above behind compound eye, ventral surface of scape, ventral spot on pedicel, pair of small spots on pronotal collar separated by 2 × MOD, pronotal lobe (margined with black), large mark anterior to mesocoxa approximately equal in area to ventral surface of mesocoxa, ventral surface of procoxa, mesocoxa except base, apical two-thirds of ventral surface of metacoxa, ventral and much of posterior surface of profemur except basal one-quarter, apicodorsal mark on pro- and mesofemora, dorsal surface and apical one-third of anterior surface of pro- and mesotibiae, anterior surface of metatibia (posterior surface orange basally, orange-brown apically, blackish ventrally), anterior surface of all basitarsi, transverse subapical bands on T1-T6, narrowly interrupted medially on T1, T4 and T5, more broadly interrupted on T2 and T3, complete on T6; irregularly-shaped subapical mark on S2, S3 band narrow and interrupted medially, junction of disc and apical sternal depressions narrowly orange brown. Second tarsomere on all legs yellowish, increasingly dark on more apical tarsomeres to red brown on pretarsus. Posterior surface of metatibia orange. Pale marking on T1 margined with orange anteriorly, marking broad laterally, restricted to narrow line medially; T2 orange for more than lateral one-third width of tergum. S2 with large orange spot on each side. Apical tergal depressions translucent, somewhat orange medially, on T1, T2 and T6 pale straw, on T3-T5 colourless all somewhat orange medially, apical sternal depressions straw yellow except of S5 yellowish.

Pubescence: As in female except as follows: suberect longer whitish setae ~MOD on genal area above and sides of mesopleuron; ~1.7 MOD on genal area below and scutellum; shorter ~MOD erect pale setae on mesoscutum, short 0.5 MOD suberect setae on T2-T6 and metasomal sterna, similar setae shorter on T1.

Surface sculpture: As in female except as follows: micropunctures abundant on S2; lateral surface of propodeum carinate for dorsal ½. Larger punctures of T1-T3 i ≤ 4d, T4 i ≤ 3d, T5-T6 <2d, T7 i <d, crowded towards apex. S2 and S5 i <6d, S3-S4 i <2d, S6 with scattered punctures i = 1-6d.

Structure: Head almost 1.5 × as wide as long, 93:64; [labrum W:L 32:14, apical margin shallowly concave;] clypeus more than 2.7 × as wide as medial length, 66:24, lip less than half clypeal width 29, slightly shorter medially than towards side; supraclypeal area entirely obscured by frontal crest in frontal view; supra-antennal area L:W 27:18, shorter than scape 31; AOD greater than maximum width of F1 13:11; frontal depression almost reaching lower tangent of median ocellus; UOD:LOD:MINOD 73:49:33; IOD:OOD 19:17; scape ~ 1.5 × as long as greatest width, 31:20; pedicel almost as long as maximum width 13:12; F1 2.5 × as long as greatest width 32:13; F2 shorter than F1,> 1.5 × as long as greatest width 28:16, remaining flagellomeres ~1.5 × as long as wide except F11 26:10, somewhat falcate, downcurved and narrowing from base to apex, apicoventral surface at ~80° to longitudinal axis of flagellum; pronotal collar more than 0.5 MOD medially, 12:20; admedian line impressed for anterior two-thirds; length of scutellum:metanotum:metapostnotum 42:16:29; scutellum posteromedial pit absent. T7 semicircular with five teeth, medial tooth the shortest and broadest, submedial teeth as long as lateral ones but broader. S2-S5 apical depressions broad submedially> 0.3 MOD on S2, longer than largest punctures on sternum, impunctate apical portion clearly longer than diameters of basal punctures. Apical sternal depressions long, on S2 longer than diameter of largest punctures on sternum; anterior and posterior angles of medial interruption of apical sternal depressions slightly acute and slightly obtuse, respectively on S2, both approximately right angular on S3-S5.

Variation.

There is minor variation in the extent of pale marking in females, some lack the medial interruption to the pale marking in front of each mesocoxa or have the metacoxa narrowly pale medially on the ventral surface. All have the red markings on T1 and T2 completely interrupted by black medially although in one male the dark marks are narrowed to <0.5 MOD on T2 and are dark brown.

Etymology.

The species is known only from moderate to high altitude in an area of the Atacama Desert that is famous for its sodium nitrate (chile saltpeter) mines. These “salitreras” give the species its name, which is a noun in apposition. These mines dotted the landscape, especially in the late 1890s and early 1900s; but are now abandoned, mostly indicated by ruins and/or just their cemeteries. The known localities for the species are all from the sides of roads that form networks among these abandoned mines in a part of the country that would otherwise be almost inaccessible.

Comments.

Two unidentified species of Tachysphex and an undescribed species of Parapiagetia were found in association with this species; none of them seem to be the same as those found associated with the other species of Cresson treated above.

This species comes from the part of the Atacama Desert where the absolute desert (rainfall less than 10 mm/yr) gets furthest inland, almost to the border with Argentina. Other species of interest from this area include the wasps just mentioned and a recently described cuckoo bee, Melectoides desiccata Packer and Graham. The type locality was imaged by Packer and Graham (2020; Fig. 9 ). The Cerro dos Hermanos locality is even drier and inhospitable.

Figures

Figure 7. Top of head of female C. salitrera. Red line: MOD; blue line IOD; yellow line OOD. Scale bar: 1.0 mm.

Figure 9. Dorsal view of mesosoma of C. parvispinosus to show landmarks for some measurements. Black line: length of pronotal collar; blue line: length of mesoscutum; red line: ITW; green line: length of scutellum; purple line length of metanotum; yellow line: length of dorsal surface of metapostnotum (note that the latter is taken from the metanotal-metapostnotal suture to the transverse carina closest to the change in angulation from approximately horizontal to approximately vertical surfaces of the metapostnotum). Scale bar: 0.5 mm.

Figure 21. Distribution map of all records of Cresson spp. Red symbols: C. parvispinosus, star: the type locality for C. parvispinosus; blue: C. mariastea; green: C. salitrera. Scale bar: 500 km.

Figures 25 - 30. Characters used to differentiate C. mariastea and C. salitrera 25 T 6 of female C. mariastea, 26 T 6 of female C. salitrera. Scale bars: 0.5 mm. 27 F 11 of male C. mariastea 28 F 11 of male C. salitrera. Scale bars: 0.25 mm. 29 base of T 2 C. mariastea 30 base of T 2 of C. salitrera. Scale bars: 100 µm.

Figures 31 - 33. Cresson salitrera 31 male, lateral view 32 holotype female, dorsal metasoma 33 male, dorsal metasoma. Scale bars: 1.0 mm.

Figures 34 - 35. Relative dimensions of MOD and pronotal collar medial length for couplet 1 of identification key of Cresson species 34 C. parvispinosus and 35 C. salitrera. Red lines MOD, blue lines medial length of pronotal collar. Scale bars: 1.0 mm.