Trimmatothelopsis novomexicana K. Knudsen, Kocourk. & Hodkova, 2023

Knudsen, Kerry, Kocourkova, Jana, Hodkova, Eva, Dart, Jason, Huereca, Alejandro & Malicek, Jiri, 2023, Three new species of Trimmatothelopsis (Acarosporales, Acarosporaceae) from southwestern North America, MycoKeys 99, pp. 251-268 : 251

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Trimmatothelopsis novomexicana K. Knudsen, Kocourk. & Hodkova

sp. nov.

Trimmatothelopsis novomexicana K. Knudsen, Kocourk. & Hodkova sp. nov.

Fig. 4 View Figure 4


Similar to Trimmatothelopsis gordensis but differs in having a contiguous epilithic areolate thallus instead of a thallus of dispersed areoles and being distinct in nrITS and mtSSU sequence data.


U.S.A., New Mexico: Eddy Co., Brokeoff Mountains Wilderness Study Area , pinyon-juniper woodland, 32.2056, -104.8418, alt. 1850 m, on Permian limestone, 27 Mar. 2022, J. Kocourková 10875 & K. Knudsen (holotype-PRM; isotype-BRY-C) GoogleMaps .


This species is named after the state of New Mexico where it was discovered.


Hypothallus with scattered algal cells. Thallus of contiguous areoles, 0.1-0.5 mm and 0.2-0.6 mm, forming patches up to 3 cm wide, or often on rough rock forming smaller patches ca 3-5 mm wide, replicating by division. Upper surface white from epicortex or brown from cortex, epruinose. Epicortex thick 25-40(-70) µm, with distinct hyphae. Cortex 30-60 µm thick, of vertical hyphae, mostly 1 µm wide, apices slightly expanded to 2 µm, upper layer usually one cell thick and light brown, lower layer hyaline, cortex sometimes completely lacking between algal layer and a thick epicortex. Algal layer of scattered algal cells 2-3(-7) µm wide, sometimes continuous or in small clusters throughout the thallus, sometimes continuous below apothecia but sometimes absent or with only a few scattered algal clusters. Medulla 100-250 µm thick, obscure with substrate crystals, hyphae ca 1-2 µm wide, a few scattered algal cells. Apothecia scattered, disc small usually 100-200 µm µm wide, without a distinct thalline ring, disc black or red, epruinose, immersed, becoming convex. Parathecium indistinct to 10 µm wide. Hymenium 200-300 µm tall, epihymenium reddish, 10 µm thick, paraphyses 1-2 µm wide with unexpanded apices, hymenial gel IKI+ red or light blue turning red, hemiamyloid, but if IKI too diluted with water on the slide the reaction is IKI- pale yellow. Asci 130-160 × 20-35 µm, cylindrical, tholus and space between inner and outer wall of ascus pale blue, with a dark blue stain in the upper layers of tholus, ascospores ellipsoid, (4.4-)4.7-5.31-5.9(-6.5) × (1.7-)1.9-2.21-2.5(-2.8) µm (n = 20), l/b 2.4. Subhymenium 0-40 tall, IKI+ blue (but reaction often negative like hymenium). Pycnidia 80-100 × 130-180 µm, multi-chambered, terminal cells of ostiole hyphae dark brown and 2.7-4.6 µm wide (Fig. 4K View Figure 4 ), conidiogenous cells 7.5-13.3 × 1.4-2.1 µm (n = 20), conidia (3-)3.5-4.27-5.0(-5.7) × (0.8-)0.8-0.99-1.1(-1.3) µm (n = 20), l/b 4.4. Not producing secondary metabolites.

Additional specimens examined.

U.S.A., New Mexico: Eddy Co., Brokeoff Mountains Wilderness Study Area, pinyon-juniper woodland, 32.2056, -104.8418, alt. 1870 m, on Permian limestone, 26 Mar. 2022, J. Kocourková 10877 & 10888 & K. Knudsen (Hb. K &K); Lincoln Co. , Carrizozo Malpais, Valley of Fires Recreation Area , at base of the sandstone slope above the lava fields, junipers common, 33.6817, -105.9247, alt. 1950 m, on reconsolidated calcareous sandstone, 24 Mar. 2020, K. Knudsen 19324 & J. Kocourková (SBBG) GoogleMaps .

Ecology and distribution.

The holotype was collected on scattered limestone rocks in full sun on a low crest in the Chihuahuan Desert in New Mexico at an elevation of 1850 m. It was growing in pinyon-juniper woodland on uplifted and eroded Permian reefs. It was associated with Acarospora peltastica and Circinaria contorta . We expect it to be locally frequent and to occur in the adjacent Guadalupe National Park in pinyon-juniper areas. It was definitely rare about 100 miles from the type locality at the Carrizozo Malpais lava beds, on calcareous reconsolidated sandstone, growing with Peltula obscurans var. deserticola , at the base of a north-facing sandstone slope with junipers at elevation of 1950 m. We studied this area extensively and only collected it once. Trimmatothelopsis novomexicana often occurred in small patches with a few apothecia among other lichens on rough limestone.


Four other species of Trimmatothelopsis have similar ascus stains with a darker blue stain in upper layers of a pale blue tholus: T. americana , T. gordensis , T. mexicana and T. wirthii . Trimmatothelopsis novomexicana differs from T. americana especially in having apothecia lacking a carbonized outer surface. Trimmatothelopsis novomexicana differs from T. gordensis especially in having areolate thallus vs. a thallus of discreet areoles. Trimmatothelopsis novomexicana differs from T. mexicana in having longer conidia and in lacking a stipe. Trimmatothelopsis novomexicana differs from T. wirthii especially in having areoles vs. large squamules up to 7 mm wide.

The narrow morphological and genetic differences between these similar species are probably based on a long geographical isolation from each other. One mystery of the protologue of Thelocarpella gordensis was a description of periphyses in the ostiole of the ascomata (see the drawing in Navarro-Rosinés et al. 1999). Our colleague Martin Westberg borrowed the holotype from Claude Roux. He was told he could photograph it (a photograph we used in this study) but could not dissect any of the areoles (Westberg, pers. comm.) Later, based on its recovery in the Acarosporaceae , the description of periphyses in Thelocarpella gordensis was treated as a misinterpretation of the incurving melanized hyphae of the parathecium merging with the cortex around the punctiform discs ( Knudsen and Lendemer 2016). In studying Trimmatothelopsis novomexicana we discovered the source of the misinterpretation of T. gordensis as a perithecioid lichen. The authors had mistaken the elongated black tips of the terminal cells of ostiole hyphae of the pycnidia for being hyphae of a perithecia (see Fig. 4J View Figure 4 ). In the specimens of T. novomexicana there is also no evidence apothecia grow out of stromata that contained pycnidia as in Sarcogyne similis H. Magn. (see pictures of the synonym Sarcogyne reebiae K. Knudsen in Knudsen et al. 2011). In the recent description of Trimmatothelopsis wirthii (see below) it is stated there are no periphyses in the “ostiole”. Roux also describes pycnidia with dark ostiole hyphae. Roux described melanized horizontal hyphae incurving from the parathecium and merged with the cortex around the punctiform apothecia as pseudopapillae ( Roux 2021).