Calyxochaetus remifer, Runyon, 2024

Runyon, Justin B., 2024, Revision of the genus Calyxochaetus Bigot (Diptera: Dolichopodidae: Sympycninae), Zootaxa 5539 (1), pp. 1-74 : 66-68

publication ID	https://doi.org/ 10.11646/zootaxa.5539.1.1
publication LSID	lsid:zoobank.org:pub:7BDB9666-CA90-40BF-8F65-B9897CDA1F2B
DOI	https://doi.org/10.5281/zenodo.14240416
persistent identifier	https://treatment.plazi.org/id/FD1A87BF-A56D-FFA6-50D3-F9A7FDA2FBE6
treatment provided by	Plazi
scientific name	Calyxochaetus remifer
status	sp. nov.

Treatment

Calyxochaetus remifer sp. nov.

( Figs 1 View FIGURES 1–4 , 110, 118 View FIGURES 104–119 , 128 View FIGURES 120–131 , 142 View FIGURES 139–143 , 148 View FIGURES 147–148 )

Type material. HOLOTYPE ♂, labeled: “ MEXICO B.C. Sur/ Guerrero Negro / II-24-74 / G.E. Bohart ”; “HOLOTYPE/ Calyxochaetus / remifer / J.B. Runyon [red label]” ( LACM) ( Fig. 142 View FIGURES 139–143 ).

Other material examined. MEXICO: Baja California: ca 28.665° -113.594°, at a desert seep, on seep monkeyflowers at night, 23.xi.2023 [photos examined: https://www.inaturalist.org/observations/192507313] .

Diagnosis. The very large, elongate oval lamella on the arista-like stylus ( Fig. 110 View FIGURES 104–119 ) and form of the fore tarsus ( Fig. 118 View FIGURES 104–119 ) in males are unique in Calyxochaetus .

Description. Male. Wing length 3.4 mm. Head: Frons brown pruinose with large glabrous shiny blue-violet spot on either side of ocellar tubercle. Face white-silver, very narrow, about one ommatidium wide at narrowest. Antenna ( Fig. 110 View FIGURES 104–119 ) brown, scape slightly shorter than postpedicel; postpedicel short and oval, slightly longer than wide; arista-like stylus with large elongate oval microtrichose apical lamella (subequal in size to postpedicel). Palpus not visible. Thorax: Pleura brown with thick gray pruinosity, sclerite below halter yellowish; metepimeron mostly yellow, lightly infuscated on about dorsal half. Scutellum with distinct blue-violet reflections medially. Legs: Foreleg: Yellow, except tarsus brown from apex of tarsomere 3. Tibia slender, without outstanding setae. Tarsus ( Fig. 118 View FIGURES 104–119 ) with tarsomere 1 very short, nearly round. Tarsomere 2 slightly more than half tibia length, about half of combined length of tarsomeres 3–5. Tarsomere 3 short (about 2X length of tarsomere 1) and slightly broadened apically. Tarsomere 4 long (about 4X tarsomere 3 length) slightly flattened, broader, and rounded on basal third (oar-shaped), with dense short pale hooked dorsal microsetulae near base, lateral edges of dorsal surface with row of larger setae. Midleg: Yellow, except coxa infuscated at base, tarsomere 5 brown. Tarsus ( Fig. 128 View FIGURES 120–131 ) with tarsomere 1 slightly more than half tibia length, longer than combined length of tarsomeres 2–5. Tarsomere 2 rather short and flattened, subequal to combined length of tarsomeres 3–4, gradually widening to apex with pointed anteroapical lobe bearing short setulae. Tarsomere 3 wider than long, subtriangular and flattened, pointed anteriorly with a few anterior setulae. Tarsomere 4 larger than tarsomere 3, flattened, with wider anterior lobe, with a few anterior setulae and some white posteroventral setulae. Tarsomere 5 slender, slightly longer than combined length of tarsomeres 3–4. Hindleg: Yellow, except tarsus yellow-brown. Tibia with two long (about 2X tibia width), slender ventral setae at base. Wing: Hyaline. Similar to C. ornatus ( Fig. 138 View FIGURES 132–138 ), except anal area slightly broader. Distal section of M 4 about 3X longer than crossvein dm-m. Abdomen: Tergites 2–3 largely yellow. Tergite 4 brown-yellow.

Female. Unknown.

Distribution and seasonal occurrence. Known from southern Baja California and northern Baja California Sur, Mexico ( Fig. 148 View FIGURES 147–148 ). The holotype was collected in February and adults were photographed in November.

Remarks. This species seems related to C. ornatus and C. tohono sp. nov., based on the form of the fore and mid tarsus. In Baja California, many adults were observed on leaves of seep monkeyflowers at night (Chloe and Trevor Van Loon, pers. comm.) ( Fig. 1 View FIGURES 1–4 ).