Introduction
Eremothecella Syd. is characterized by dark brown to black ascomata with loose paraphysoids, globose asci that generally protrude through the ascoma surface as small warts, and applanate pycnidia with long filiform, multiseptate conidia which distinguish it from Arthonia (Sérusiaux Reference Sérusiaux1992; Lücking Reference Lücking2008). The genus was established by Sydow (Reference Sydow1917) but synonymized with Arthonia by Santesson (Reference Santesson1952). Sérusiaux (Reference Sérusiaux1992) reinstated Eremothecella and included four species. Lücking (Reference Lücking2008) also preferred to maintain Eremothecella as a separate genus because of Eremothecella-type pycnidia. Of the eight species currently known, six are foliicolous and two corticolous and until now the genus has not been reported from India.
In the course of a recent floristic review of the lichens of the Andaman and Nicobar Islands, while studying the foliicolous species of Arthonia s. lat., several distinct species of Eremothecella were encountered. Detailed studies revealed that two species were new to science and three others represented new records for India. The new species are described below and brief notes on the new records are provided. A worldwide key to species of Eremothecella is presented. Thus, the total number of species in the genus becomes ten, seven of which are known from the eastern Paleotropics.
Materials and Methods
Specimens were collected in the Andaman and Nicobar Islands by one of the authors (TAMJR) and deposited in PBL and CAL. External morphological features were observed with an Olympus SZ61 stereomicroscope. Thin hand-cut sections of thalli were mounted in water, 10% KOH solution (K), Lugol's iodine solution (0·5 g iodine and 1·5 g potassium iodide in 100 ml distilled water) (I) and lactophenol cotton blue (LCB) then examined with a Nikon Eclipse 50i light transmission microscope. Thallus colour reactions were carried out using 10% aqueous potassium hydroxide solution (K), aqueous calcium hypochlorite solution (C) and Steiner's stable solution (P). Lichen substances were studied by thin-layer chromatography (Orange et al. Reference Orange, James and White2001).
The New Species
Eremothecella ajaysinghii Jagad. Ram & G. P. Sinha sp. nov.
MycoBank No.: MB 832114
Foliicolous Eremothecella similar to E. macrocephala but with 8–10(–11)-septate, (33–)36–50(–52) × (7–)8–10(–12) μm ascospores.
Type: India, Andaman Islands, North Andaman, Kalara forest, elev. 62 m, 23 April 2011, T. A. M. Jagadeesh Ram 315 (CAL—holotype; PBL—isotype).
(Fig. 1)
Thallus crustose, foliicolous, dispersed or continuous, rounded to irregular in outline, 10–40 mm diam., smooth, greenish grey to green or whitish grey, thin, matt, lacking distinct prothallus, ecorticate, 12–25 µm thick. Photobiont cells in radiate plates, rectangular, 8–15 × 4–6 µm, forming ±continuous plates.
Eremothecella ajaysinghii (holotype). A, thallus with ascomata; B, thallus with pycnidia; C, asci and ascospores; D, conidia. Scales: A & B = 1 mm; C & D = 10 µm. In colour online.
Ascomata few to many, rounded to irregular, plane, slightly prominent, dark brown to black, ±moderately to densely greyish pruinose, pruina sometimes increasingly dense along the margin, 0·4–1·1 mm across, 45–80 µm thick. Epithecium pale to dark brown, incrusted with numerous small colourless to sordid green granules (pruina) dissolving in K, 6–10 µm thick, I+ red, KI+ pale blue. Hymenium pale brown, 40–72 µm high, I+ intensely orange-red, KI+ blue then quickly yellow. Hypothecium pale brown, 5–10 µm thick, I+ orange-brown, KI+ ochraceous yellow. Paraphysoids branched and anastomosing, 1·0–1·5 µm wide. Asci globose to subglobose, 8-spored, 40–72 × 38–60 µm, I+ orange, KI+ pale blue in inner parts of tholus. Ascospores colourless, becoming brownish and wrinkled, clavate, 8–10(–11)-septate, somewhat curved, distal cell enlarged, with very slight constrictions at septa, (33–)36–50(–52) × (7–)8–10(–12) μm.
Pycnidia numerous, applanate, elliptical to ±rounded, irregular, black, 0·2–0·5 × 0·2–0·3 mm. Conidia colourless, filiform, one end wider than the other, multiseptate, 70–125 × 1·5–2·0 µm.
Chemistry
Thallus K−, C−, KC−, P−; no lichen substances detected by TLC.
Remarks
Eremothecella ajaysinghii is very close to E. macrocephala (R. Sant.) G. Thor et al., which also has pruinose ascomata and 9–13-septate ascospores, but the latter species has larger ascospores (52–74 × 8–15 µm). Eremothecella cyaneoides Lücking and E. variratae (Aptroot & Sipman) Sérus. are other species having ascomatal pruina; however, E. cyaneoides has smaller, 3–5-septate ascospores, while in E. variratae the ascomata have an orange-yellow pruina (Santesson Reference Santesson1952; Aptroot & Sipman Reference Aptroot and Sipman1991; Thor et al. Reference Thor, Lücking and Matsumoto2000; Lucking et al. Reference Lücking, Streimann and Elix2001). The new species has been commonly found in the shaded parts of evergreen forests in both the Andaman and Nicobar Islands. It usually grows on the leaves of palms, including Calamus species and Korthalsia laciniosa, plus Donax canniformis, Garcinia nervosa, Heritiera littoralis and some other dicotyledons in the dense to open shady understorey of evergreen and mangrove forests.
Etymology
The species is named in honour of the late Dr Ajay Singh, a renowned Indian lichenologist who established the lichenology division and lichen herbarium in the National Botanical Research Institute, Lucknow and was a pioneer in the study of lichens of the Andaman and Nicobar Islands in the post-independence period.
Additional specimens examined
India:Andaman and Nicobar Islands: North Andaman, Diglipur, Khalighat, on Heritiera littoralis, elev. 10 m, 2011, Jagadeesh Ram 437 (PBL). Middle Andaman, Mayabunder, Tugapur forest, 2012, Jagadeesh Ram 838 (PBL); South Andaman, Baratang Island, Nayadera mangrove forest, 2012, Jagadeesh Ram 2272 (PBL); ibid., 12°05′95·0″N, 92°44′53·6″E, 2013, Jagadeesh Ram 2627 (PBL). Little Andaman: Vishnu Nala Dam forest, 2012, Jagadeesh Ram 1712B (PBL). Car Nicobar Island, Passa forest, 9°12′75·3″N, 92°45′66·5″E, elev. 8 m, 2014, Jagadeesh Ram 3896 (PBL); Perka, 9°10′64·1″N, 92°46′98·7″E, elev. 8 m, 2014, Jagadeesh Ram 3982 (PBL); ibid., 9°10′59·8″N, 92°47′03·2″E, elev. 10 m, 2014, Jagadeesh Ram 3987 (PBL); Katchal Island, E-Wall forest, 7°59′67·0″N, 93°23′81·7″E, elev. 15 m, 2014, Jagadeesh Ram 3715 (PBL); Little Nicobar Island, School Point forest, 7°24′31·7″N, 93°42′71·2″E, elev. 5 m, 2014, Jagadeesh Ram 4311 (PBL); Great Nicobar Island, Shompen Hut forest, 6°58′94·4″N, 93°51′03·5″E, elev. 30 m, 2014, Jagadeesh Ram 3314 (PBL); Afra Bay forest, 7°10′97·7″N, 93°44′27·9″E, elev. 30 m, 2014, Jagadeesh Ram 4451 (PBL); Murray Point forest, 7°13′62·2″N, 93°48′74·3″E, elev. 10 m, 2014, Jagadeesh Ram 4485 (PBL).
Eremothecella nicobarica Jagad. Ram & G. P. Sinha sp. nov.
MycoBank No.: MB 832115
Foliicolous Eremothecella similar to E. macrosperma but with (14–)15–17-septate, 60–72 × 10–13 µm ascospores.
Type: India, Nicobar Islands, Great Nicobar Island, East West Road, Shompen Hut forest, 6°58′87·9″N, 93°51′79·5″E, elev. 10 m, 30 May 2015, T. A. M. Jagadeesh Ram 3298 (CAL—holotype; PBL—isotype).
(Fig. 2)
Thallus crustose, foliicolous, dispersed into ±rounded, confluent patches or irregular in outline, smooth, 15–50 mm across, pale greenish grey to pale green, thin, matt, lacking distinct prothallus, ecorticate, 10–20 µm thick. Photobiont cells angular-rounded to rectangular, 7–14 × 3–6 µm, in irregular or sometimes radiate plates.
Eremothecella nicobarica (holotype). A & B, thallus with ascomata; C, thallus with pycnidia; D, conidia; E, asci; F, ascospores. Scales: A–C = 1 mm; D–F = 20 µm. In colour online.
Ascomata few to many, sharply delimited, hardly raised above thallus level, rounded to irregular in outline, 0·5–1·3 mm diam. and 70–120 µm thick, dark brown to blackish brown, non-pruinose. Epithecium formed by a layer of densely packed, parallel, periclinal hyphae, dark brown, 5–12 µm thick, K+ sordid brown, I+ orange-brown, KI+ ochraceous yellow. Hymenium pale brown, 70–110 µm high, I+ intensely orange-red, KI+ blue then quickly yellow. Hypothecium brown, 5–12 µm thick, I+ orange-brown, KI+ ochraceous yellow. Paraphysoids branched and anastomosing, 1·0–1·5 µm wide. Asci obovate to globose, 65–100 × 52–70 µm, I−, KI+ pale blue in inner parts of tholus. Ascospores colourless, clavate, curved, (14–)15–17-septate, distal cell enlarged, with very slight constrictions at septa, 60–72 × 10–13 µm.
Pycnidia few, applanate, oval to drop-shaped, 0·2–0·4 × 0·2–0·3 mm, black. Conidia colourless, filiform, one end wider than the other, multiseptate, 60–120 × 1·5–2·0 µm.
Chemistry
Thallus K−, C−, KC−, P−; no lichen substances detected by TLC.
Etymology
The specific epithet refers to its inventory from the Nicobar Islands.
Remarks
Eremothecella nicobarica is distinct from all the other species by the (14–)15–17-septate ascospores. It is similar to E. macrosperma (Zahlbr.) Sérus., which also has non-pruinose ascomata, but differs in its 7–12-septate ascospores. Eremothecella calamicola Syd. is another species lacking ascomatal pruina but it has smaller, 5–7-septate ascospores (Santesson Reference Santesson1952; Lücking Reference Lücking2008). The new species is known by the type collection and is found on dicotyledonous leaves in the shady understorey of an evergreen forest on Great Nicobar Island.
New Records
Eremothecella calamicola Syd.
This pantropical species was commonly found in the shaded parts of evergreen forests in both the Andaman and Nicobar Islands. It usually grows on the leaves of Calamus, Korthalsia laciniosa, Pinanga manii and some dicotyledons in the understorey communities. It is characterized by non-pruinose ascomata and 5–7-septate ascospores (30–45 × 7–10 µm).
Specimens examined
India:Andaman and Nicobar Islands: South Andaman, Havelock Island, Kala Pathar forest, 2012, Jagadeesh Ram 2101 (PBL). Kamorta Island, Vikas Nagar – Pillpillow forest, 6°58′95·8″N, 93°51′59·8″E, elev. 15 m, 2014, Jagadeesh Ram 3475 (PBL); Katchal Island, E-Wall forest, 7°59′67·0″N, 93°23′77·8″E, elev. 15 m, 2014, Jagadeesh Ram 3717A (PBL); ibid., 7°59′67·0″N, 93°23′81·7″E, elev. 15 m, 2014, Jagadeesh Ram 3731 (PBL); ibid., 7°59′70·5″N, 93°23′63·4″E, elev. 15 m, 2014, Jagadeesh Ram 3733 (PBL); Little Nicobar Island, Akupa forest, 7°22′65·4″N, 93°39′79·8″E, elev. 10 m, 2014, Jagadeesh Ram 4226 (PBL); School Point forest, 7°24′31·7″N, 93°42′71·2″E, elev. 5 m, 2014, Jagadeesh Ram 4312 (PBL); Pulopattia forest, 7°19′37·7″N, 93°43′49·0″E, elev. 15 m, 2014, Jagadeesh Ram 4373 (PBL); Great Nicobar Island, Shompen Hut forest, 6°58′87·1″N, 93°51′25·1″E, elev. 30 m, 2015, Jagadeesh Ram 3313 (PBL); Nature Trail forest, 7°00′20·3″N, 93°52′80·3″E, elev. 10 m, 2014, Jagadeesh Ram 3334 (PBL); ibid., 7°00′31·0″N, 93°52′76·7″E, elev. 25 m, 2014, Jagadeesh Ram 4574 (PBL); Afra Bay forest, 7°10′97·7″N, 93°44′27·9″E, elev. 30 m, 2014, Jagadeesh Ram 4448 (PBL).
Eremothecella macrosperma (Zahlbr.) Sérus.
This species was previously known from Indonesia, Japan and Papua New Guinea. It was found on the leaves of Heritiera littoralis and Calamus in the shaded parts of mangrove and evergreen forests in both the Andaman and Nicobar Islands. It is characterized by non-pruinose ascomata and 7–12-septate ascospores (35–60 × 9–14 µm).
Specimens examined
India:Andaman and Nicobar Islands: North Andaman, Diglipur, Radhanagar II seashore, on the way to Nayakattai, on Heritiera littoralis, elev. 5 m, 2011, Jagadeesh Ram 286 (PBL). Katchal Island, E-Wall forest, 7°59′67·0″N, 93°23′81·7″E, elev. 15 m, 2014, Jagadeesh Ram 3714 (PBL); Great Nicobar Island, Afra Bay forest, 7°10′73·6″N, 93°44′29·4″E, elev. 30 m, 2014, Jagadeesh Ram 4453 (PBL).
Eremothecella variratae (Aptroot & Sipman) Sérus.
This species was previously known from Papua New Guinea and was found on the leaves of Calamus, Mangifera, Korthalsia laciniosa and Pinanga manii in the shaded understorey of evergreen forests in the Nicobar Islands. It is characterized by the orange-yellow pruinose ascomata and 5–7-septate ascospores (28–42 × 7–10 µm).
Specimens examined
India:Andaman and Nicobar Islands: Little Nicobar Island, Akupa forest, 7°22′ 65·7″N, 93°39′80·4″E, elev. 5 m, 2014, Jagadeesh Ram 4242 (PBL); Pulopanja forest, 7°19′41·8″N, 93°43′45·6″E, elev. 28 m, 2014, Jagadeesh Ram 4370 (PBL); Pulopattia forest, 7°19′36·9″N, 93°43′51·1″E, elev. 5 m, 2014, Jagadeesh Ram 4382 (PBL); Great Nicobar Island, Afra Bay Forest, 7°10′96·3″N, 93°44′29·7″E, elev. 20 m, 2014, Jagadeesh Ram 4438 (PBL).
World key to the species of Eremothecella
1 Thallus foliicolous……………2
Thallus corticolous……………9
2(1) Ascospores transversely septate……………3
Ascospores muriform…Eremothecella cingulata (R. Sant.) Ferraro & Lücking
3(2) Ascomata densely whitish grey or orange-yellow pruinose……………4
Ascomata non-pruinose……………7
4(3) Ascospores 3–7-septate……………5
Ascospores 8–13-septate……………6
5(4) Ascomata whitish grey pruinose; ascospores 3–5-septate, 25–35 × 8–10 μm……………Eremothecella cyaneoides Lücking
Ascomata orange-yellow pruinose; ascospores 5–7-septate, 28–42 × 7–10 µm……………Eremothecella variratae (Aptroot & Sipman) Sérus.
6(4) Ascospores 8–10(–11)-septate, (33–)36–50(–52) × (7–)8–10(–12) μm……………Eremothecella ajaysinghii Jagad. Ram & G. P. Sinha
Ascospores 9–13-septate, 52–74 × 8–15 µm……………Eremothecella macrocephala (R. Sant.) G. Thor et al.
7(3) Ascospores 5–7-septate, 30–45 × 7–10 µm……Eremothecella calamicola Syd.
Ascospores 7–17-septate……………8
8(7) Ascospores 7–12-septate, 35–60 × 9–14 µm……………Eremothecella macrosperma (Zahlbr.) Sérus.
Ascospores (14–)15–17-septate, 60–72 × 10–13 µm……………Eremothecella nicobarica Jagad. Ram & G. P. Sinha
9(1) Pycnidia 0·2–0·4 mm diam.; conidia usually helicoid; ascomata unknown……………Eremothecella helicella Aptroot & M. Cáceres
Pycnidia 0·1–0·2 mm diam.; conidia not helicoid; ascomata 0·5–1·0 mm diam.; ascospores 3-septate, microcephalic, 16–21 × 6–7 µm……………Eremothecella microcephalica Sipman
We are grateful to Dr R. Lücking for his comments on the new species and sending relevant literature; the Director, Botanical Survey of India, Kolkata and the Head, BSI, Andaman and Nicobar Regional Centre, Port Blair for the use of facilities; the Authorities of the Department of Environment & Forests, Andaman and Nicobar Islands for facilitating the fieldwork; Dr Siljo Joseph, NBRI, Lucknow for assistance with literature.
