Micro- Coryphia and Zygentoma: Insecta) in the Eastern Atlantic Islands
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ídCop~rghl13ü3 oy Univers 1, a' Seia . 5 ena . 113 y 3 INTERVATIONAL SEUl'iA.il ON APTERYGOTA R Dal'ai cdilor e. REMARKS ON THE FAUNlSTlC DlVERSlTY OF THE THYSANURANS (MICRO- CORYPHIA AND ZYGENTOMA: INSECTA) IN THE EASTERN ATLANTIC ISLANDS L.F. MENDES Faculty of Sciences of Lisboa/Portugal, Depart m ent of Zoology and A nthro- pology. Centro de Zoologia of the I.I.C.T. Fellow of the I.S.I.C. / PL3 INTR O D U CTIO N FISCHER -et -al (23) were the first ones to investigate faunistic diversity creating an e index to relate the number of species and subspecies of a zoo- logical group and the number of studied specimens in a certain area. Later, M ARGALEFF (25) proposed his 0 index which, although theoretically not so COL rect as the former, is much easier to utilize. Quite similar in their results, thg se two methods share, however, two negative points: both impose the number of studied specimens (com monly unlcnown) and both neglect the surface of the analysed area; this last item, seems particularly important when faunistic divo sities of countries with very different areas are compared and, particularly, in the case of islands -see also (24). This same problems, led RIBEIRO to investi- gate (52) and to apply (53) a new < index, calculated by the formula s= E-1 log& + 1) being E the number of studied taxa, A the analysed area and 2 the base of the natural logarithms. M ETH O DS Trying to apply this last index to the thysanuran faunas of the eastern at lantic islands, 1 faced a further problem: is the area A the addition of the in- dividual areas of all the isiands of each archipelago ? or will it be the total area covered by the archipelago ? The problem seems more evident when we try to co m pare "short" or "CO m pact" archipelogoes (like the M adeira-Porto San- to-Desertas), with isolated islands (as St. Helena or Fernando Poo) and "diffusel' archipelagoes (like the Azores). So, as this problem concerns directly the effect --of area, 1 propose to utilize a close but disünct formula, similar to that of RIBEIRO but which, 1 believe, will "soften" the problem. In this new Kindex 1 propose to work with both areas, A, the surface of the terra firme (the sum of the individual island areas) and A', the surface of the archipelago as a whg le, as follows: J' = E-1 A + A' 10% ( + 1) 2 This new index is reduced to its original form when isolated islands (v.g. St.Helena, Principe, S.Tho m e) are investigated. c In this paper, diversity indexes are calculated independently to EIIC R OCO R Y PHIA and to Z Y GEh'TO hI A (quite distinct groups in the phylogenetic but al- so in the ecological point of view). Two indexes are, further, calculated to each one of these Orders, one concerning the total number of known taxa, the other the probably autochthon species only - excluding, then, the cosmopolitan and tropicopolitan species and the obviously introduced taxa. To each one of the studied archipelagoes, we will present the folloriing four indexes: e,the mo- dified RIBEIR O index to the total HIC R OC OR Y PHIA which num ber of species 127 is EN; 'bll ,.the modified RIBEIRO index to the probably autochthon NICRO- COTTPHeS;;?.~hich number of known species is m: D,the modified RIBEIRO index to the ZY GENTON A, being its number of species and a,the modi- fied RIBEIRO index to the non introaliced ZYGENTONA, which number of spe- cies is G. R ECU LTC Subsquently, the known thysanuran faunas of XIC R OC O R Y PHIA and Z Y- GES'TO>IA in the eactern atlantic islands are presented (TABLES 1 and 2). Machilinus ?kleinenbergi Machilinus portosantensis '. Machilinus rupestris ssp. ' ,. '?Neomachilellus? gestroi . Pseudomeinertellus feae .. ~ ' :' Pseudomeinertel lus gradweli \; y % .Pseudomeinertellus snowi Oilta altenai Dilta hybernica Dilta insulicola Dilta littoralis Dilta saxicola Janetschekilis dolichopsis Janetschekilis grandipalpus Lepismachi 1 is ssp. í?) Metagraphitarsus doriae Parapetrobius aroricus Petrobius brevistylis Petrobius maritimus Trigoniophthalmus alternatus TOTAL 1A 4A 5A ?3A 2A - 3A ?1B 2A 1A 4A - TABLE 1 - Known distribution of the species of MICROCORYPHIA in the eastern atlantic islands. A- Probably autochthon species; A*- Endemics; B- Almost certainly * introduced species. (MADEIRA (1) = Porto Santo t Desertas). Yone data are available from the folloking isiands, where no thysanurolo- gical prospections have been camed: Ano Bom (=Pagalu), in the Guinea Gulf, where some speciec muct be found in the future; Ascendon, very wide apart from the african and the brazilian coasts where, as it happens with St.Helena, a few species might be present; Trictan da Cunha, Gough and Bouvet, where, due to their geographical isolation and known climate, we beiieve quite probab- ly that none species (with the eventual exception of synanthropic introduced pg 128 Acrotelsa collaris Afrolepisma wygodzinskyi Ctenolepi sma ciliata Ctenolepisma diversisquamis Ctenolepi sma dubitalis Ctenolepisma feae Ctenolepisma lindbergi Ctenolepi sma 1 ineata Ctenolepisma longicaudata Ctenolepisma sanctaehelenae Ctenolepisma unistila Ctenolepisma vieirai Ctenolepisma sp. 1 Lepisma saccharina Monachina stylifera ssp. -- Neosterolep. myrmcobia Neosterolep. pelagodromae Neosterolepisma sp. 1 Prolepismina pulchella Thermobia aegyptiaca Therbobia domestica Gastrotheus seticeps Gastrotheus brachyurus Gastrotheus nanus Grassiella modesta Luratea aequatorial is O1 arthrocera brevicauda Proatelurina pseudolepi sma Santhomesiella thomensis Hematelura gestroi Subnicoletia feae TOTAL 10 28 38 2A+ 2.41 3At gA+ 3A 9A+ 2At 28 18 18 BE 28 38 TABLE 2 - Known distribution of the species of ZYGENTOM in the eastern atlantic islands. A, A*, 8, E* and HAOEIRA (1) as in TAELE 1. c pulations) would occur. The faunas of the remaining archipeiagoes are more or les well known, with the exceptions of those from Fernando Po0 and Principe. 20 species of PíIC R O C O R Y PHIA (fa m. bl einerteiiidae and blachilidae) and 31 species of Z Y G E N T O M A (fa rn . Le pis m atidae, A telundae and Nicoletiidae) are known to occur in the studied insular entities; these data have been obtained through the following origins: to ICELAN D (59); to IRELAN D (9)(10)(llX18)(63); to G R E A T B RIT AIN (3X5)(8)(12Xi3)(14)(1~)(17)(18)(19)(22X27)(28)(42X45)( 50)(51)(62)(63) ; to the AZORES (26)(31)(41)(56)(64)(69); to E.lADEIRA+PORTO SANTOtDESERTAS 129 (i)(4)(29X31)(45X47); to the SALVA G ES (29X31X36); to the C A N.A RfES (2X3X31X43) (44)(45)(46X54X64X65)(68); to C A PE VER DE (2lX31X32X33X34X35X44X57X67); to FERh'AWDO PO0 (57); to PRINCIPE (57); to S. THOME (37X38X39X4OX57X66); and to ST. HELEKA (30)(70) In TABLE 3 are exposed the values of tema firme area (A) and of the to- tal area (A)of each one of the archipelagoes (or isolated islands) and also the result oE the natural logarithm calculated upon these two surfaces. The appro- ximate distance to the nearest mainland and the probable age are also presen- ted, IR ELA S D and G R EAT B RITAIN excluded as these islands are part of the eurasian shield and have been, in quite recent times, in dú-ect connection with AcA' A (Km') A' (Km') log (- +l AGE (MY) Oistance to mainland e2 ICELANO 102 828 102 828 4.633 20 400 Kn (Greenland) 800 Km (N.England) IRELANO 84 419 84 419 11.344 _-_ continental isl. GREAT BRITAIN 230 O00 230 O00 12.346 --- continental isl. AZORES 2 304 53 704 10.240 20 1.650 (Portugal) MAOE IRA (1 1 781 5 170 7.998 90 600 (Marocco) SALVAGES 8 45 '3.211 32 345 (Marocco) CANARIES 7 484 97 500 10.868 32 115 (Harocco) CAPE VERDE 4 023 63 112 10.421 1 O0 600 (Senegal 1 FERNANDO PO0 2 O17 2 017 7.610 120 30 (Nigeri a-Kameroon j PRINCIPE 114 114 4.745 120 215' (Rio Uuni-Kamroor S. THOME 857 857 6.755 120 280 (Gaboon) ST. HELENA 123 123 4.816 20 1 850 (Namibia-Angolal TABLE 3 - Areas, ages and distances to nearest mainland of the eastern atlantic islands. A, A' and e accordingly to the text. (HAOEIRA (1) = Hadeira+Porto SantoiOesertas) "MI ICELANO 1 1 O O 1 O O O 1RE LAN O 4 4 0.265 0.265 O O O O GREAT BRITAIN 5 5 0.324 O. 324 2 o 0.080 O AZORES (*) 3 3 0.195 0.195 3 O 0.195 O MAOEIRA (11 2 2 0.125 0.125 4 2 0.375 0.125 SALVAGES O O O O 3 2 0.610 0.305 CANAR I ES 3 3 0.184 0.184 4 3 0.276 0.184 CAPE VERDE 1 O O O 16 8 1.439 0.672 FERNANDO PO0 2 2 0.131 0.131 3 3 0.263 0.263 PRINCIPE 1 1 O O O O O 0- S. THOME 4 4 0.444 0.444 11 9 1.480 1 .la4 ST. HELENA O O O O 5 2 0.831 0.208 TABLE 4 - Number of knoun species of total and autochthon HICROCORYPHIA (EM and E',,) and of ZYGENTOMA (EZ and E'Z) in the eastorn atlantic islands and ¿* diversity fndexes. (*) If Oilta and Lepismachilis ssp. are considered os introduced, the 6 indexes uill be reduced to O. MAOEIRA (1) = MadeirwPorto Santo+Oesertas 130 the neighbouring continental areas. These values are based in (7)(20)(55)(58) and e. (60). DIS C U CSIO N TABLE 4 shows the calculated values of to the total and to the pro- bably autochthon species of MIC R O C O R Y PHIA and of Z Y G EN TO El A in the ana- lysed insular entities.