Stamnodes costimacula (Grossbeck, 1912)

Figs 31, 94–95

Petrophora costimacula Grossbeck, 1912: 283 . Type locality: San Diego, California, USA. [AMNH]. Stamnodes kelseyi Wright, 1927: 41 . Type locality: Pine Valley, San Diego County, California, USA.

[SDNHM].

Stamnoctenis costimacula pallula McDunnough, 1941: 70 . Type locality: The Geysers, Sonoma County, California, USA. [CNC].

Stamnodes costimacula – McDunnough 1938: 151 (checklist). — Furniss et al. 1988: 9. — Scoble 1999:

901 (catalogue). — Scoble & Hausmann 2007 (online catalogue). — Lee 2014: e86 (inventory). — Pohl et al. 2016: 449 (checklist). — Rajaei et al. 2022 (online catalogue).

Stamnoctenis kelseyi – McDunnough 1938: 151 (checklist); 1941: 70.

Stamnoctenis costimacula – McDunnough 1941: 70. — McFarland 1965: 62 . — Ferguson 1983: 103 (checklist). — Poole & Gentili 1996: 686 (checklist).

Stamnodes kelseyi – Furniss et al. 1988: 9.

Diagnostic remarks

Males can be separated from those of S. annellata, S. coenonymphata, and S. cassinoi by their bipectinate antennae.

Distribution

Mexico: Stamnodes costimacula is found in the chaparral associations, foothills, canyons, and Pacific coastal scrub communities of northwestern Baja California. USA: the core of this species’ range lies in California.

Biology

The peak adult flight is October to December with mature larvae following into March and April. Larvae are hosted by birch leaf mountain mahogany ( Cercocarpus betuloides). The caterpillar and host plant were discovered by David L. Wagner and the author in March 2016 in southern California. Additional unpublished life history details and larval illustrations are forthcoming (Matson & Wagner in prep.).

Molecular characterization

This species is presently represented in BOLD by multiple BINs. The BIN that includes topotypic San Diego Co. (USA) individuals is: BOLD:AAN0096 (n = 13). At present, the average pairwise intraspecific distance is 0.63% and the distance to the nearest neighbour, Stamnodes costimacula pallula (n = 6), is 2.81%.

Remarks

COI barcode data show significant phylogeographic divergence across the range of S. costimacula . Nuclear markers are necessitated to further circumscribe and scale this genetic variation. Without significant isolating barriers, it can be assumed that topotypic individuals barcoded from San Diego Co., California, represent the same population as that in northern Baja California.