Dicranocentrus, Schott

Silva, Clécio Danilo Dias Da, Nunes, Rudy Camilo, Winck, Bruna Raquel & Bellini, Bruno Cavalcante, 2024, A new species of Dicranocentrus Schött (Collembola, Orchesellidae) from the Brazilian Pampa, with a key to the gracilis-group taxa, Zootaxa 5471 (5), pp. 536-554 : 550-551

Identification key and distribution of the Dicranocentrus species from the gracilis- group*

1 Dens without spines................................................................................... 2

- Dens with spines.................................................................................... 10

2 Th. II–III with 16 and 11 central mac, respectively............................ D. indecisus Mari-Mutt, 1985 ( Nepal)

- Th. II–III with 5–15 and 6–10 central mac, respectively...................................................... 3

3 Abd. III with 1 central mac, tibiotarsi with several smooth chaetae............................................… 4

- Abd. III with 2–3 central mac, tibiotarsi without smooth chaetae**............................................. 5

4 Dorsal head P group with 6 mac, Th. II with 11 central mac, tenent hairs acuminate.. D. assimilis Schött, 1927 ( Cameroon)

- Dorsal head P group with 4 mac, Th. II with 12 central mac, tenent hairs capitate..... D. inermis Schött, 1927 ( Cameroon)

5 Dorsal head P group with 9 mac, Th. II–Abd. I with 5, 6 and 2 central mac, respectively, manubrium with smooth chaetae.......................................................... D. singularis Mari-Mutt & Bhattacharjee, 1980 ( India)

- Dorsal head P group with 10–11 mac, Th. II–Abd. I with 11–15, 9–10 and 3–6 central mac, respectively, manubrium without smooth chaetae...................................................................................... 6

6 Abd. IV with 5–6 central mac........................................................................... 7

- Abd. IV with 2–4 central mac........................................................................... 8

7 Dorsal head P group with 10 mac, Abd. III–IV with 2 and 6 central mac, respectively.................................................................................. D. deharvengi Mari-Mutt, 1981 in Mari-Mutt (1981c) ( Nepal)

- Dorsal head P group with 11 mac, Abd. III–IV with 3 and 5 central mac, respectively..... D. thaicus Yosii, 1961 ( Thailand)

8 Labial m2 chaeta smooth, ungues with three inner teeth...... D. violaceus Mari-Mutt, 1981 in Mari-Mutt (1981c) ( Nepal)

- Labial M2 chaeta ciliate, ungues with four inner teeth........................................................ 9

9 Dorsal head P group with 11 mac, Abd. I–II with 4 and 3 central mac, respectively.......................................................................................... D. fraternus Mari-Mutt & Bhattacharjee, 1980 ( India)

- Dorsal head P group with 10 mac, Abd. I–II with 3 and 2 central mac, respectively........................................................................ D. nepalensis Mari-Mutt, 1980 in Mari-Mutt & Bhattacharjee (1980) ( Nepal)

10 Dorsal head P group with 8 mac, Th. II and Abd. I with 14 and 6 central mac, respectively............................................................................................... D. gapudi Mari-Mutt, 1985 ( Philippines)

- Dorsal head P group with 7 or less mac, Th. II and Abd. I with 9–13 and 3–5 central mac, respectively................ 11

11 Dorsal head P group with 6 mac, Abd. III with 1 central mac.......... D. meruensis Wahlgren, 1908 ( Tanzania, Ethiopia)

- Dorsal head P group rarely with 6 mac, usually with 1–5 or 7 mac, Abd. III with 2 central mac...................... 12

12 Abd. I with 3 central mac............................................................................. 13

- Abd. I with 5 central mac............................................................................. 15

13 Dorsal head P group with 5 mac, Th. II–III with 13 and 9 central mac, respectively.................................................................................................. D. luzonensis Mari-Mutt, 1985 ( Philippines)

- Dorsal head P group with 1 mac, Th. II–III with 10 and 6 central mac, respectively................................ 14

14 Ungues internally only with proximal paired teeth......................... D. bidentatus Mari-Mutt, 1983 ( Venezuela)

- Ungues internally with the median tooth, some specimens also with the apical one................................................................................................. D. paramoensis Mari-Mutt, 1983 ( Venezuela)

15 Dorsal head P group with 6 mac, Th. II–III and Abd. IV with 9, 11 and 4 central mac, respectively........................................................................... D. nigritus Mari-Mutt, 1979 in Mari-Mutt (1979b) ( Peru)

- Dorsal head P group usually with 2–5 mac, rarely with 6–7 mac, Th. II–III and Abd. IV with 11–14, 9–10 and 5–6 central mac, respectively........................................................................................ 16

16 Th. III with 10 central mac, dens with 10–14 spines organized in 1 row......................................................................................... D. delamarei Mari-Mutt, 1981 in Mari-Mutt (1981a) ( Ivory Coast)

- Th. III with 8–9 central mac, dens with 28 or more spines organized in 2 or more rows............................. 17

17 Th. III with 8 central mac, dens with about 77 spines..................... D. longicornis ( Carpenter, 1916) ( Seychelles)

- Th. III with 9 central mac, dens with 28–64 or about 110 spines............................................... 18

18 Th. II with 11 central mac, dens with 28 spines............................ D. gracilis Schött, 1893 ( Cameroon, Peru)

- Th. II rarely with 11 central mac, usually with 12–14, dens with 44 or more spines................................ 19

19 Specimens strongly pigmented, Th. II with 14 central mac...................... D. orellanae Jacquemart, 1980 ( Peru)

- Specimens never strongly pigmented, Th. II with 11–13 central mac........................................... 20

20 Th. II and Abd. IV with 11 and 6 central mac, respectively....... D. schoetti Mari-Mutt, 1979 in Mari-Mutt (1979b) ( Peru)

- Th. II and Abd. IV with 12–13 and 5 central mac, respectively................................................ 21

21 Basal labium with scales.............................................................................. 22

- Basal labium without scales........................................................................... 26

22 Labial basomedian field with 9–11 chaetae, Abd. III with 3 central mac............ D. capitaneus Mari-Mutt, 1985 ( Peru)

- Labial basomedian field with 6–8 chaetae, Abd. III with 2 central mac.......................................... 23

23 Dorsal head P group with 6–7 mac, internal labral papillae apically rounded............. D. pampaensis sp. nov. ( Brazil)

- Dorsal head P group with 3–4 mac, internal labral papillae apically acuminate................................... 24

24 Labial R chaeta ciliate, labial basomedian field with 6 chaetae and 4 scales......... D. platensis ( Izarra, 1972) ( Argentina)

- Labial r chaeta smooth, labial basomedian field with 7 chaetae and 5–6 scales................................... 25

25 Dorsal head P group with 4 mac, Th. II with 12 central mac, tibiotarsi without smooth chaetae**, ungues without the internal apical tooth................................... D. colombiensis Mari-Mutt, 1979 in Mari-Mutt (1979b) ( Colombia)

- Dorsal head P group with 3 mac, Th. II with 13 central mac, tibiotarsi with smooth chaetae, ungues with the internal apical tooth............................................................ D. heloisae Arlé & Mendonça, 1982 ( Brazil)

26 Th. II with 13 central mac, trochanteral organ with about 100 spine-like chaetae, dens with about 60 spines............................................................................. D. magnus Xisto & Mendonça, 2017 ( Brazil)

- Th. II with 12 central mac, trochanteral organ with about 70 or less spine-like chaetae, dens with about 50–55 or 110 spines. .................................................................................................. 27

27 Dorsal head P group with 4 mac, ungues with the apical tooth, dens with about 110 spines.......................................................................................... D. marimutti Xisto & Mendonça, 2017 ( Brazil)

- Dorsal head P group with 2 or 5 mac, ungues without the apical tooth, dens with about 50–55 spines................. 28

28 Labial chaeta r smooth, dorsal head P group with 2 mac, trochanteral organ with about 70 spine-like chaetae............................................................................. D. cuprum Xisto & Mendonça, 2016 ( Brazil)

- Labial chaeta R ciliate, dorsal head P group with 5 mac, trochanteral organ with about 40 or 65 spine-like chaetae....... 29

29 With 3 interocular chaetae, labial M1 chaeta ciliate, m2 smooth, tenaculum chaeta smooth, trochanteral organ with about 40 spine-like chaetae, tenent hairs acuminate......................... D. albicephalus Xisto & Mendonça, 2017 ( Brazil)

- With 4 interocular chaetae, labial m1 chaeta smooth, M2 ciliate, tenaculum chaeta ciliate, trochanteral organ with about 65 spine-like chaetae, tenent hairs capitate............................... D. melinus Xisto & Mendonça, 2016 ( Brazil)