Calosoma (Castrida) linelli Mutchler, 1925

Length 12-13 mm. C. linelli seems to represent the most morphologically differentiated taxon among the species typical of the environment of the high ground terminal of the islands Galapagos, and the most clearly genetically separated one. The results of genetic analysis too confirm that the oldest divergence separates C. linelli , namely the highland species of the oldest island, from the remaining species (Hendrickx et Al, 2015).
C. linelli has flight wings reduced to a narrow rudiment with wing musculature completely absent, it is small, depigmented, with no seta on the pronotum.
It is endemic of Galápagos archipelago and is localized, at around 570- 700 m., on the summit of the island San Cristobal (Chatham), which it is the oldest of the islands as its age is estimated between 4 and 2.4 million years.

Examined specimens
Galápagos Archipelago (Ecuador). San Cristobal (Chatam): El Junco 660 m.(AVT); San Cristobal, pampa 500-700m (IRScNB)

Notes: The rear wings of C. linelli are completely atrophied It is predator on ground dwelling invertebrates. Most specimens have been found in open ground with few shrubs. Most probably it is nocturnal and can be found wandering on trails at night and can be captured with pitfail traps. Sometimes it is met in activity in the day but more often it is hidden under stones and debris. Active specimens were captured in June, October and in February, but according to Peck (2006: 106) the species should be active between January and May.
C. linelli has been noted as host of the fungus Laboulbenia flagellata Peyritsch. It has been suggested that this is due to occasional predation on the much more frequently-parasitized Platynus calathoides as well as Platynus darwini that co-occur in the fern-sedge zone at higher elevations of the island (Arndt and Desender, 2002: 158).
The species has been named after Martin Larsson Linell (1849-1897) assistant at National Museum of Natural History, Washington.

Calosoma (Castrida) linelli ♂ Mutchler, 1925 Galápagos archipelago, San Cristobal Is., El Junco 660m. (sous pierre), 4.X.85, Pierre Moret lgt. (coll Vigna Taglianti)