Crematogaster marioni

This species is apparently entirely arboreal, and possibly nests only in live oak and in manzanita, if available records are a sufficient sample (Buren 1968).

Identification
Buren (1968) - There is no other species in California or Baja California with which marioni is likely to be confused. It does seem close to Crematogaster isolata, which will be described below, but is perfectly distinct, especially in pilosity, and there would seem no chance for confusion.

Key to Crematogaster of the western United States

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Nomenclature

 *  marioni. Crematogaster (Crematogaster) marioni Buren, 1968b: 105 (w.) U.S.A.

Worker
Length about 2.8 to 3.3 mm.

Head, excluding mandibles, a little longer than broad or as long as broad, with moderately convex sides and posterior border straight or nearly so. Scapes scarcely surpassing hind corners. Second funicular joints longer than broad but third to fifth, at least, broader than long. Shoulders of pronotum usually weak or inapparent. Pro-mesonotum in profile above evenly but weakly convex, without mesonotal declivity or this very short. Mesoepinotal impression, nevertheless, rather strong. Mesonotal carina evident in front only, moderate to strong and sharp. Epinotal spines of moderate length, shorter than interbase. Spines not slender, nearly always straight, divergent, and horizontal, not tilted upward. Base of epinotum long; in profile often somewhat convex and with small impressions just preceding the bases of the spines. Petiole little broader than long, no more than one and one-third broader in any specimen measured, and rather angulately trapezoidal; an anterio-ventral tooth present. Hemilobes of postpetiole rather elongate, more produced to the rear and semi-angulate there, straight sided, with faint spiracular angles. Gaster rather slender.

Head sculpturing rather weak. Genae striato-punctate to about middle of eyes, thereafter weakly punctate past the eyes. Head smooth and shining on venter and corners, subshining and faintly punctate on front, vertex, and middle of occiput. Front of pronotum with weak irregular rugae. Dorsum of pronotum rather weakly punctate and subopaque. Sides of pronotum very weakly punctate or striato-punctate, subshining. Mesonotal dorsum weakly punctate. Mesopleura punctate and with moderate rugae or striae. Metapleura punctate with faint striae below, striato-punctate above. Base of epinotum punctate with a few strong longitudinal striae; declivity shining, faintly punctate. Postpetiole punctate with striae on the dorsum. Gaster smooth and shining.

Pubescent hairs long and rather coarse, appressed or subappressed on most surfaces including scapes and legs, on petiole more erect, on gaster subappressed and a little curved or reflexed. Erect hairs weakly bristlelike, short; on thorax three to six hairs on each shoulder and two to four at rear of mesonotum. These apparently easily rubbed and lost, as many specimens lack them. On gaster numerous and scattered on first segment, in the usual rows on remaining segments. Postpetiole usually with accessory pairs besides the constant posteriodorsal pair.

Head dark brown, thorax somewhat lighter. Gaster dark brown.

Type Material
Holotype worker and numerous paratypes from several nests in either dead manzanita stems or branches or on live oak at Morena Lake, San Diego Co., Calif., W. F. Buren. The species is also represented by numerous specimens collected by Dr. Wm. S. Creighton, which I have also marked as paratypes, from 13 mi. E. of Tecate, Baja California, Mex.; Dripping Springs Camp Ground, Aguatibia Mts., Calif. (3 colonies); Cameron Corners, San Diego Co., Calif.; and Canyon City, San Diego Co., Calif.; all these records from live oaks. I have also marked as paratypes a few specimens from Robertson Creek, Monterey, Calif., and have seen specimens from Santa Barbara, Pasadena, and San Ysidro, Calif. The holotype and a few paratype specimens are to be sent to the National Museum. Other paratypes will be sent to the Museum of Comparative Zoology, American Museum of Natural History, California Academy of Natural Sciences, and the personal collection of Dr. Creighton. I will retain paratypes from each series.

Etymology
C. marioni is named in honor of one of our foremost myrmecologists, Dr. Marion R. Smith, now retired.