Dermatoglyphic patterns and pattern intensities of the genus Cacajao (Cebidae platyrrhini) with observations on interspecific and subspecific differentiation.код для вставкиСкачать
American Journal of Primatology 19:25-37 (1989) Dermatoglyphic Patterns and Pattern Intensities of the Genus Cacajao (Cebidae, Platyrrhini) With Observations on lnterspecific and Subspecific Differentiation LAURA NEWELL-MORRIS',' AND THOMAS F. WIENKER' 'Department of Anthropology and Regional Primate Research Center, University of Washington, Seattle; "Institut fur Humangenetik und Anthropologie der Universitat Freiburg, Freiburg, Federal Republic of Germany Palmar and plantar dermatoglyphic pattern types, area and total pattern intensities (API and TPI), and pattern intensity (PI) profiles are presented for the South American genus Cacajao of the subfamily Pitheciinae. The data are based on prints from 41 bald-head uacaries (C. calvus), 9 white bald-head uacaries (C. c. calvus), and 15 black-head uacaries (C. melanocephalus). In each extremity, loops of differing orientation were the most frequent pattern type; whorls were dominant a t palmar interdigital (I) area 3 in C. calvus and a t both I3 and I4 in C. melanocephalus. Open fields characterized the palmar thenar and plantar proximal hypothenar, thenar, calcar, and I3 and 14. There was little evidence of significant sexual dimorphism a s assessed from PI values. The genus displayed significant asymmetry a t palmar I3 (P 5 0.001) and plantar distal hypothenar ( P 5 0.004). There were significant group differences between C. calvus and C. c. calvus in the palmar thenar API and plantar TPIs. The combined baldhead sample of C. calvus and C. c. calvus differed from C. melanocephalus in API of palmar I4 and plantar distal thenar, 12, and distal hypothenar (marginally), and in plantar TPIs. In PI profiles, C. melanocephalus departed from the pattern shared by C. calvus and C. c. calvus in both palmar and plantar interdigital areas. As a genus, the uacaries have markedly low plantar TPI values relative to palmar values (palm-sole index > 195). Of eight comparison cebid genera, only Chiropotes, another pitheciine genus, approximated these values. Key words: New World monkeys, taxonomy, uacaries INTRODUCTION Nonhuman primates display a variety of dermatoglyphic patterns on the volar surfaces of their hands and feet. These patterns differ not only between genera but also between species, making them a potentially useful morphologic feature for taxonomic studies. In this paper we describe the dermatoglyphics of the South Received for publication May 23, 1989; revision accepted August 2, 1989 Address reprint requests to Kate Elias, Publications Editor, Regional Primate Research Center SJ-50, University of Washington, Seattle, WA 98195. 0 1989 Alan R. Liss, Inc. 26 I Newell-Morris and Wienker American uacari (Cacajao). The two classic monographs on nonhuman primate dermatoglyphics [Midlo & Cummins, 1942; Biegert, 1961I do not include this genus, and this report presents the first description of the palmar and plantar dermatoglyphic pattern types and their distribution in Cacajao. The analysis was facilitated by Hershkovitz’s  comprehensive review and revision of the taxonomy of Cacajao, in which he identified two species within the same genus, i.e., the black-head uacari (C. melanocephalus) with two subspecies and the bald-head uacari (C. caluus) with four subspecies. Of the latter, C. c. caluus previously had been designated a separate species (C. caluus) and the remainder grouped within the species C. rubicundus [cf. Napier & Napier, 19671. Hershkovitz’s nomenclature is followed throughout this report. In addition to a general description of the dermatoglyphic pattern types and intensities characteristic of the genus, we present a comparison between C. melanocephalus and C . caluus; a small sample of the white bald-head subspecies (C. c. caluus) is also compared with each of the two species to determine the extent of subspecific differentiation. MATERIALS AND METHODS Genus Cuca&w: General Distribution and Description The genus Cacajao is distributed throughout the upper Orinoco and Amazonian regions in Venezuela, Colombia, Peru, and Brazil. The two species, C. caluus and C. melanocephalus, are probably allopatric. The latter is restricted to the northeast sector of the generic range in eastern Colombia, the upper Rio Orinoco basin of Venezuela, and the Rio Negro-upper Rio Solim6es basin of Amazonas, Brazil. The white bald-head subspecies is confined to the varzea forest of a small “island” formed by the lower section of the right bank of the Rio Japura, the left bank of the Rio Solimijes, and the Auati-Parana [Ayres, 19861. For complete distribution maps see Hershkovitz [1987, pp. 4, 61. The uacaries are the largest of the nonprehensile-tailed platyrrhines, but have the shortest tails. They are grouped within the subfamily Pitheciinae along with the two saki genera, Chiropotes and Pithecia. A number of tegmentary, skeletal, and dental features, singly or in combination, distinguish Cacajao from the related pitheciine forms. Uacaries are the only non-agouti-colored pitheciines. The larger of the two species, C. caluus, is reddish orange, buffy, or whitish in general coloration and presents a striking appearance with its bare, unpigmented face that appears scarlet red in sunlight. In contrast, the more hirsute C. melanocephalus has a blackish forehead and crown covered with dark hair and is blackish in general coloration. The uacari hand is prehensile; the morphological axis lies between the index and middle fingers, and the thumb and index finger move in tandem [Hershkovitz, 19721. The thumb, although nonopposable, can grasp small objects by pressure contact at the interphalangeal joint or thenar pad [Napier & Napier, 19671. The locomotor behavior of the uacaris is not well known. They are broadly classified as quadrupedal [Napier & Napier 19671. Oxnard  places them among the primate species that rely on equal use of the fore- and hindlimbs. Individuals have been observed in suspensory behavior using either fore- or hindlimbs and can cover short distances by bimanual suspensory locomotion [Hollihn, 19841. They also resort occasionally to bipedalism [Stern, 19711. Samples The dermatoglyphic materials were obtained from live animals housed in zoos and research facilities and from preserved specimens in museums and anatomical Dermatoglyphics of Cacq'ao I 27 institutes throughout Europe and the United States (see Acknowledgments). The taxonomic classification and site where each animal was collected were checked against current nomenclature and known geographic distribution. Any specimen of questionable status was rejected. The final sample consisted of 65 uacaries including 41 C . calvus (18 males, 22 females, 1 sex unknown), 9 C . c. catvus (3 males, 6 females), and 15 C . melanocephalus (8 male, 7 female). Dermatoglyphic Data The dermatoglyphic features of the right and left palms and soles were printed by standard inking technique or recorded in schematic drawings done a t the time of visual inspection of the volar surfaces. All prints and drawings had been recorded and interpreted by H. Brehme (Institut fur Humangenetik und Anthropologie der Universitat Freiburg, FRG) several years before the present analysis. Standard nomenclature was used for the volar areas and dermatoglyphic pattern types [Midlo & Cummins, 1942; Biegert, 19611 with slight modifications [Brehme & Wittmann, 1980; Newell-Morris & Wienker, 19861. Pattern types were assigned pattern intensity (PI) values from 0 to 1.0 a t intervals of 0.20, after Midlo and Cummins . According to this scheme, the higher the PI value, the more complex the pattern. When more than one pattern covered a single volar area, the areal value was obtained by summing the individual values of the component patterns; the combined maximal value was 1.0. Where two pads were fused into a single structure, that part of the fused pad covered by most of the pattern was assigned the value of the respective pattern; the other part was given the value 0.20. If the pattern was evenly distributed across the fused area, each component pad received the full PI value of the shared pattern. Statistics A mean areal pattern intensity (API) value was calculated separately by sex and by side (left and right) for each of the seven palmar and nine plantar pad areas. Total pattern intensities (TPIs) were computed, two for the palm and two for the sole. TPI6 was derived from the API values for the six primary areas of the palm (proximal hypothenar, thenar, and four interdigital areas [I1 to 141) and from the six homologous areas of the sole. TP17 was obtained from the API values for the six primary areas of the hand plus the nonprimary distal hypothenar area; TPI9 was obtained from the API values of the six primary areas of the foot plus the three nonprimary areas-the distal hypothenar, calcar, and distal thenar. Palmar and plantar API and TPI values were tested for significant side differences by a nonparametric matched-pairs test (Wilcoxon's ranked-signs test); sex and group differences were tested by a nonparametric location test (Mann-Whitney U test) [Hull & Nie, 19811. The probability of P < 0.05 for the null hypothesis was chosen as the acceptable level of significance. The PI data were analyzed on the 1100/82 Sperry UNIVAC computer with the standard SPSS9 statistical program package [Nie et al., 19751. Note that whereas the PI data are presented as arithmetic means to enable comparison with other published results, the nonparametric tests employed are sensitive mainly to differences in the medians of the samples. RESULTS Pattern T y p e s The distributions of pattern types by left palmar and plantar areas, sex-combined, are given for each of the three groups in Tables I and 11. The patterns at each area are arranged from the most to the least frequently observed basic types; the 28 I Newell-Morris and Wienker TABLE I. Distribution of Pattern Types: Palmar Areas Left Side, Sex-Combined, Cacajao C. caluus ( n = 41) Volar area C . melanocephalus C . c . caluus in = 9) (n = 15) (Hd)” Lp(28) VLp(4) Lpr(1) O(7) V(1) Lp(5) VLpil) O(2) V(1) Lp(12) VLp(1) O(1) fus HP Th - - Lu(40) VW(1) O(33) Lrd(2) LdLp(1) V(1i Ld(4) Ld(8) LdLd(2) LdlV(1) Lrd,V(l)W(G) accW(3) tzWi1) VW(3)V/Wi2) LdWi3) VLd,W(l) LrdW(2)W,W(l)Si3) W(17) VW(1) Ld(15) VLdil) 0(2)Lp(l) VLp(1) 5x1) VS(1) V(1) W(16) VW(3) Lp(8) VLp(1) Ld(7)0(6) Lp(21) S(7) W(5) VW(1) 0(3)0/V(1)V/Ox( 1) Ld(1) V(1) VLp(1) Lu(8) Lud(1) 0131 Ld(3) Lrd(1) LpLu(1) Lu(13) Lud(1) O(9) Ox(l) Lrd(2) Ld(1) fus I1 I2 I3 I4 4u Ld(2) Ld(3) O(2) Will VS(1) Ld(2) S(6) W(2) tzW(2) W,V(1) Ld(l)O(l) W(2) VW(1) Ld(2) 0 i 2 ) VLp( 1)S(1) Ld(7) O(3) Lp(2) W(2i Vil) Lp(4) VLp(1) O(2) W(1) V(1) Lp(4) VLp(1) V(2) Ldil) VLdi 1) W(7) Ld(3) Oi2) Lp(1) S(l)V(l) W(11) S(2) Ld(1) VLp(1) - - Abbreviations: Volar area-4f, marginal fibular accessory pad of 14; 4u, marginal ulnar accessory pad of 14; C, calcar; CA:4p, central accessory pad proximal to 14; fus, fused pads; Hd, distal hypothenar; Hp, proximal hypothenar; I, interdigital (11,12,13,14);Th, thenar; Thd, distal thenar; Thp, proximal thenar. Pattern type-A, arch; accW, accidental whorl; Ld, distal loop; Lf, fibular loop; Lp, proximal loop; Lr, radial loop; Lt, tibia1 loop; Lu, ulnar loop; 0, open field; Ox, arch over partially reduced radiant; S, double loop, double centric whorl; tzW, tricentric whorl (of three Loops); V, vestigial pattern (type not identifiable); VW, VLp, etc., vestigial pattern type; VIW, etc., vestige plus whorl; W, unicentric whorl; LdLd, LdW, etc., combined double pattern. More complete descriptions of these terms are to be found in Biegert L19611 and Brehme and Wittmann . “Nonprimary area. variations of a basic pattern type are presented immediately adjacent to it, e.g., proximal loop (Lp) and proximal radial loop (Lpr). Palmar Areas (Table I) For the genus Cacajao, the proximal loop is the almost exclusive pattern of the nonprimary hypothenar distal area, whereas the ulnar loop prevails in the proximal hypothenar area. The thenar area is generally patternless; occasionally it is fused with the first interdigital pad. A wider range of pattern types and more interspecific differences are found at 11-14. For the two C. caluus groups, the most common pattern types are distal loops and whorls at I1 and 12, whorls and proximal loops at 13, and proximal loops at 14. C. melanocephalus appears to differ in that double loops predominate at I1 and whorls at 14. Plantar Areas (Table 11) For all species of the genus, the proximal loop is the dominant pattern type at the nonprimary distal hypothenar area; open fields occur in equally high frequencies among C . c. caluus and C. melanocephalus. Absence of patterning typifies the proximal hypothenar, calcar, and proximal thenar areas. At the nonprimary distal thenar area, open fields and loops in equal frequencies characterize C. caluus, Dermatoglyphics of Cacajao I 29 TABLE 11. Distribution of Pattern Types: Plantar Areas Left Side, Sex-Combined, Cacqjao Volar area C. calvus (n = 41) (Hd)" C. c. calvus (n 9) C . melanocephalus (n = 15) O(8) Lp(5) LpLp(1) V(1) fus HP (C)" ThP (Thd)" I1 I2 I3 O(12) Ld(3) I4 4f CA:4p Abbreviations are as in Table I "Nonprimary area. whereas only open and vestigial fields are observed in C. melanocephalus. At 11, the genus is typified by proximal loops followed in frequency by open fields. At 12, the dominant patterns are proximal loops in C. calvus and open fields in C . melanocephalus. At I3 and 14, open fields predominate throughout the genus. Pattern Intensity Sexual dimorphism. Significant sex differences were demonstrated for only two areas, both on the right foot: the hypothenar area in C. calvus and I1 in C. melanocephalus. Within the former, the difference is attributable to four females that had bilaterally fused distal-proximal hypothenar pads. Here the hypothenar area, which is generally patternless, was assigned the PI value of 0.20, thereby elevating the mean female value for the area (API = 0.06) significantly above that of males (API = 0.00, P = 0.036). The second sex difference at I1 in C. melanocephalus was only marginally significant (P = 0.044).The lower mean female API value (0.371 vs. 0.725 in the male) was attributable to the presence of vestigial loops, whereas the full loop pattern predominated among males. Combining groups did not decrease any P value to the level of significance. In conclusion, the statistical evidence was judged insufficient to warrant presentation of the data separated by sex. Lateral asymmetry. When each of the three groups was tested separately, only the palmar I3 area in C. calvus showed a significant difference between sides (Table 111).Addition of C. c. calvus to the C. calvus sample increased the P value to 0.05 for 13, but decreased it to significance (0.036) for the plantar distal hypothenar. Combining all data from the two species further decreased the P values for 30 I Newell-Morris and Wienker TABLE 111. Bilateral Palmar Pattern Intensity Values Grow C. calvus (n = Side (HdY L .61 2.05 54 2.06 51 2.12 .44 %.ll .68 t.07 .64 2.07 41) R C. c. calvus (n = 9) L R C. melanocephalus (n = L 15) R HD .80 k.01 .81 2.01 .80 2.00 .82 i.02 .81 5.01 .83 k.02 f S.E., Sex-Combined, C a c u ~ b o Th I1 I2 I3 I4 TPIG TP17 .13 5.05 .20 5.05 ,513 2.13 .49 2.14 .29 k.10 .35 5.11 .94 2.03 .81 1.04 .73 2.05 .62 5.14 .82 5.11 .63 t.10 .67 t.10 .74b 2.05 .83b k.05 .53 2.13 .62 5.12 .76 2.10 .85 2.06 .76 5.04 .68 2.05 ,518 k .09 .69 2.11 .95 2.04 39 5.07 4.17 5.10 4.12 2.14 3.62 5.33 4.13 *.38 4.33 2.19 4.57 2.18 4.78 2.12 4.66 k.16 4.13 5.34 4.58 2.39 5.01 5.20 5.21 t.20 .88 2.03 56 5.13 .69 2.14 .89 k.07 .99 2.01 "Nonprimary area, not included in computation of TPIG. hSignificant side difference, P = 0.031 (Wilcoxon matched-pairs ranked-signs test) both areas (palmar 13, P 5 0.001; plantar distal hypothenar, P = 0.004). Combining samples in this manner did not lower the P values to significance a t any other area. In summary, the results from the three groups appear internally consistent and suggest that slight asymmetry characterizes the dermatoglyphic system of the genus Cacajao. TPI and API The palmar and plantar TPI and API mean values and their standard errors (S.E.), right and left sides, sex-combined, are given for each of the three Cacujao groups in Tables I11 and IV. The absolute palmar and plantar TPIG values for the two species fall within the ranges defined by eight other South American cebid genera (Fig. 1).Within the cebid assemblage, however, plantar TPI values of the uacaries are noticeably low (52.20) relative to palmar values (24.00). This differential is expressed by the high palm-sole index (palmar TPIG/plantar TPIG x loo), which is especially pronounced in C. melanocephalus (index = 291). Only the Chiropotes values (index = 194) approximate the Cacajao values. In the hand, intermediate (20.50, 50.74) to high (20.75) API values characterize the distal hypothenar and interdigital areas; values at the thenar area range from low (C. caluus, 50.20) to intermediate (C. c. caluus). In the foot, API values for the distal hypothenar area are low to intermediate, whereas the proximal hypothenar, calcar, and proximal thenar areas approximate zero, reflecting the lack of patterning in these areas. At the distal thenar area, the API values are very low (50.10 in C. melanocephalus) to intermediate. Values for the plantar interdigital areas vary more across the individual pads than do those of the palm and range from high (I2 of C. caluus) to low (I3 throughout the genus). The highest interdigital value is found a t I1 in C. melanocephalus but at I2 in the two C. caluus samples. Testing for significant group differences in the hand showed only one significant bilateral difference between C. caluus and C. c. caluus, viz., at the thenar area; other significant differences were confined to one side (Table V). In the foot, the two C. caluus samples differed significantly in both TPI values, primarily because of Dermatoglyphics of Cuccqjao I 31 TABLE IV. Bilateral Plantar Pattern Intensity Values Group Side (Hd)" Hp C. calvus (n = L 41) R C. c. calvus (n = L 9) R C. melanocephalus (n = L 15) R .64 k.05 .53 2.06 .31 5.13 .27 ?.13 .35 ?.11 .12 2.07 .03 2.01 .04 5.02 .OO 2.00 .OO 5.00 .OO 2.00 .OO k.00 (C)" Thp (Thd)" .02 2.02 .03 +.02 .OO k.00 .OO k.00 .OO 1.00 .OO 5.00 .35 .OO k.00 2.07 .OO .41 t . 0 0 2.07 .31 .OO t . 0 0 2.13 .18 .OO z.00 2.12 .00 .04 2.00 k.02 .07 .OO 2.00 &.03 & S.E., Sex-Combined,Cacqjao I1 I2 I3 I4 .22 .56 .75 .19 2.06 2.04 2.05 2.05 .25 .22 5 3 .72 2.06 2.04 k.06 2.05 .36 .38 .42 .OO 2.14 2.12 *.OO t . 1 4 .33 .36 .49 .OO 2.14 2.14 k.00 2.13 .16 .I7 .55 .27 2.10 2.10 2.09 t . 0 8 .56 .24 .21 .32 2.09 k.09 lt.10 t . 0 9 TPI6 2.35 2.13 2.25 2.14 1.47 k.27 1.44 2.29 1.49 2.21 1.45 2.27 TP19 2.75 k.16 2.72 2.17 1.78 k.30 1.62 2.33 1.53 k.20 1.52 t.27 =Nonprimary area, not included in computation of TP16 the lower PI values of C. c. calvus a t 11-14. Group differences at the distal hypothenar were confined to the left side. Comparison of the hands of C. calvus with those of C. melanocephalus yielded significant interspecific differences only at 14. More differences were noted in the foot, i.e., at the distal hypothenar, distal thenar, and I2 areas and in both TPI values. C. c. calvus differed significantly from C. melanocephalus in the hand at I2 and I4 and marginally at I3 and in the foot only at the distal thenar. When the two C. calvus samples were combined, only the palmar I4 and plantar distal thenar and I2 areas remained significantly different from those of C. melanocephalus; significant group differences at the plantar distal hypothenar area were one-sided (right). Each significant interspecific difference can be explained entirely on the basis of the differences between the larger C. calvus sample and C. melanocephalus, as addition of the C. c. calvus subspecies did not decrease the P values. PI Profiles The PI profiles, which are graphic representations of the PI values from the left palm and sole (Tables 111and IV), are shown in Figures 2 and 3. Although there are group differences in absolute PI values, it is obvious that the overall palmar profiles are similar for the two C. calvus samples. Conversely, the profile describing C . melanocephalus departs from those of C. calvus in its increasing gradient of areas I3 and I4 relative t o I1 and 12. The peak value observed at 14 in C. melanocephalus was also shown earlier to differ significantly from the values of both C. calvus samples (Table V). In plantar profiles, the two C. calvus samples are identical, although the API values of C. c. calvus are consistently lower, as was also indicated by the significantly lower TPI values (Table V). Again, C. melanocephatus diverges from C . calvus in possessing the highest API value a t 11, whereas the highest value for each of the C. calvus groups i s a t 12. This difference is partially reflected in the significant interspecific differences a t I2 (Table V). DISCUSSION Because the samples used in the present study were compiled from diverse sources, they might be considered a random sampling of the species in question. On the other hand, a single field expedition often brought back several specimens from 32 I Newell-Morris and Wienker Cacajao melanocephalus (291) Cacajao calvus Chiropotes satanas Lagothrix lagotricha Ateles panascus Ateles geoffroyi Ateles belzebuth Ateles fusciceps Alouatta villosa Alouatta seniculus Alouatta caraya Alouatta belzebul Cebus apella Cebus capucinus Cebus albifrons S a i m i r i sciureus Aotus trivirgatus Callicebus torquatus Callicebus moloch u (132) (128) 5.0 4.0 3.0 2.0 1.0 0 0 PALMAR TPIG 1.0 2.0 3.0 4.0 5.0 PLANTAR TPIG Fig. 1. Left palmar and plantar mean total pattern intensity (TPI6) values for 19 species ( 9 genera) of New World cebid monkeys. The mean palm-sole index (palmar TPIGiplantar TPIG x 100)is given in parentheses after each species. Values for Callicebus from Newell-Morris and Wienker [ 19861, Aotus and S a m i r i from Biegert [ 19611, Cebus from Newell-Morris and Wienker I1987 I, Alouatta from Brehme and Newell-Morris 11981a1,Ateles and Lagothrir from Brehme and Newell-Morris I1981bl, Chiropotes from Brehme 119651, and Cacajao from the present study. The C. caluus values include those of C . c. culuus. the same collecting site; therefore, it is entirely possible (although not testable) that related animals were included. For still other reasons discussed in previous publications [Newell-Morris & Wienker, 1986, 19871, the results presented here are to be interpreted with caution. These reasons include small sample sizes, the arbitrariness of the scoring system used for assigning PI, the information lost by collapsing different pattern types into the same PI value, and the lack of detailed knowledge about locomotor, positional, and manipulative behaviors. Yet, to the extent that the results are internally consistent and comparable with other pub- Dermatoglyphics of Cacqjao I 33 TABLE V. Significant P Values for Subspecific and Interspecific Comparisons of PI Values, Cuccqiao* Palmar Groups Side c. calvusb vs. C . c. calvus C. caLvusb vs. C. rnelanocephalus C. c . calvus vs. C. melanocephalus Th I1 I2 I3 I4 0.004 0.029 0.001 0.110 0.764 0.052 0.004 0.007 0.301 0.027 - 0.094 0.021 0.034 0.647 0.001 0.001 0.000 0.039 0.000 0.001 - c. calvus" vs. C. melanocephalus - 0.040 0.658 - - 0.069 0.052 TPI6 TP17 0.031 0.187 - Plantar Groups C. caLvusb vs. C . c. calvus C. caLvusb vs. C. rnelanocephalus C. c . calvus vs. C. rnelanocephalus C. calvus" vs. C. rnelanocephalus Side (Hd)" 0.009 0.067 0.018 0.001 0.065 0.003 (Thd)" - 0.025 0.020 0.041 0.937 0.018 0.038 I2 TPI6 TPI9 0.005 0.111 0.000 0.000 0.008 0.016 0.001 0.005 0.020 0.008 0.000 0.000 0.000 0.000 0.007 0.020 0.001 0.002 *Significant if P 5 0.05 for a t least one side, Mann-Whitney, U test. "Nonprimary area. bC.c a l m s excluding C. c. caluus. 'C. caluus including C. c. caluus. lished data, certain conclusions can be drawn concerning the dermatoglyphic system of Cacajao. The absence of strong statistical evidence for significant sexual dimorphism in PI values agrees with earlier results obtained for the cebid genera of Callicebus [Newell-Morris & Wienker, 19861 and Cebus [Newell-Morris & Wienker, 19871. Some statistically significant sex differences have been reported for Old World Cercopithecidae, including long-tailed macaques (Macaca fascicularis) [Cauble & Mavalwala, 19731 and baboons [Brehme & Wittmann, 19801. However, the extent of sexual dimorphism in the dermatoglyphic system of nonhuman primates has not been explored. The statistical analysis did indicate some asymmetry in PI within the genus Cacajao, albeit in only two areas, one palmar and one plantar. Similarly, within the genera Callicebus and Cebus we found no evidence for pronounced or widespread asymmetry in PI [Newell-Morris & Wienker, 1986, 19871. Midlo and Cummins  also noted marked differences in the magnitude of asymmetry in PI among the several primate genera they described, but they did not test the values statistically. Among Old World primates, only data from M . fascicularis have been statistically analyzed; the results showed significant asymmetry in whorl orientation in some areas [Cauble & Mavalwala, 19731. However, to the extent that significant asymmetry does occur in the dermatoglyphics of the volar surfaces, its possible relation with functional sidedness has not been investigated. In overall TPI values, the genus Cacajao appears distinctive among South American cebids (with the exception of another pitheciine genus, Chiropotes) in its very high palm-sole index. The high value is attributable to the relatively low 34 I Newell-Morris and Wienker i: (Hd) Hp Th I1 C calvus C c calvus C melanocephalus I2 I3 I4 PALMAR AREA (left) Fig. 2. Pattern intensity profiles for seven palmar areas of the left hand, sex-combined for two species (C. caluus and C. rnelanocephalus) and one subspecies C. c. caluusi. Plotted values are those ofTable 111. Nonprimary areas are in parentheses. plantar PI values and is suggestive of possible intermembral functional differences. Yet, the few reports describing the locomotion and morphology of uacaries emphasize equal use of the two extremities [cf. Oxnard, 19861. The apparent disagreement between the dermatoglyphic data and the morphometric and behavioral data may be due, on the one hand, to a dissociation of dermatoglyphic pattern from function or, on the other, to a n overgeneralization of the activities involved in locomotion and manipulation [cf. Oxnard, 19861. The original question raised by Midlo and Cummins  as to whether significant interspecific differences exist in pattern frequencies and intensities has been answered affirmatively with respect to a number of genera [Brehme & Wittmann, 1980; Newell-Morris, 1979; Newell-Morris & Wienker, 1986, 19871, including Cacajao in the present study. Dermatoglyphic differentiation a t the subspecific level has also been noted [Newell-Morris & Kerr, 19741. However, the implications of these group differences are not clear. In particular, interdependence of the various discrete volar areas confounds interpretation of the results. In addition, it is currently not possible to determine whether the differences are associated with functional variability or are attributable to stochastic evolutionary processes such as genetic drift. Recent studies of nonhuman primates at subgeneric levels have noted behavioral differences and have started to identify some of the associated morphological adaptations Icf. Oxnard, 19861. However, conclusions regarding the adaptive advantage of morphological features, including the dermatoglyphic system, remain primarily speculative because of a lack of detailed information on the behavior of species in their natural habitats, including the three uacari groups described here. While a functional interpretation [Newell-Morris, 19791 cannot be Dermatoglyphics of Cacajao I 35 1.00 0.80 L 0.60 3 a 4 0.40 0.20 0.00 (Hd) Hp (C) Thp (Thd) I1 12 I3 I4 PLANTAR AREA (left) Fig. 3. Pattern intensity profiles for nine plantar areas of the left hand, sex-combined for two species (C. calvus and C. rnelanocephalus) and one subspecies (C. c . calvusJ. Plotted values are those of Table IV. Nonprimary areas are in parentheses. excluded, the model of isolated refuges created by repeated dry periods during the glacial epoch [Kinzey, 1982 I posits conditions under which genetic drift could operate as a major evolutionary process in the differentiation of New World primate groups. Perhaps more indicative of the genetic similarity or dissimilarity of groups are the PI profiles. In this regard, the two C . calvus groups resemble each other, whereas C. melanocephalus bears less resemblance to either. These results support Hershkovitz's [ 19871 taxonomic revision of the genus in which the two previously distinct species C . caluus and C. rubicundus [Napier & Napier, 19671 are assigned to a single species, C. caluus, and C . melanocephalus retains its specific status. The dermatoglyphic differences between C. calvus and C. c. calvus were primarily those of absolute PI values rather than of PI profiles. This degree of divergence might be expected under the conditions of geographic isolation postulated by Hershkovitz , whereby the albinotic subspecies (C. c. caluus) evolved from a saturate, pheomelanic population of C. calvus (probably C . c. rubicundus). In conclusion, the results presented here and elsewhere suggest that dermatoglyphic data may be a useful supplementary morphologic feature to be considered in taxonomic analysis. CONCLUSIONS 1. The distribution of dermatoglyphic pattern types is presented for three groups of the genus Cacajao. The two bald-head uacari groups ( C . calvus and C. c. caluus) differ from the black-head species (C. melanocephalus) a t several volar areas of the hand and foot. 36 I Newell-Morris and Wienker 2. Nonparametric statistical testing of API and TPI values yielded little evidence for sexual dimorphism; some bilateral asymmetry is present in the palms and soles. 3. Compared with eight other cebid genera, Cacajao most resembles Chiropotes (also of the pitheciine group) in TPI6 values and a low palm-sole index. 4. Statistically significant group differences were demonstrated with respect to API and TPI values, particularly in the foot. The PI profiles were similar for the two C. calvus groups, while the PI profiles of C. melanocephalus diverged from those of C. caluus at the interdigital areas in palm and sole. 5. Results from the dermatoglyphic data are consistent with Hershkovitz’s 119871 revised taxonomy of Cacajao. ACKNOWLEDGMENTS This study was completed while the senior author was on academic leave from the Department of Anthropology, University of Washington, Seattle. H. Brehme provided the data, without which the analysis could not have been done. The following museums, institutes, and zoos gave generously of their facilities: Mus. Naturk., Berlin; Field Mus. Nat. Hist., Chicago; Stattl. Mus. Tierk., Dresden; Mus. Zool., Florence; Senckenberg Mus., Frankfurt; Anat. Inst., Frankfurt; Mus. d’Histoire Natur., Geneva; Zool. Mus., Hamburg; Zool. Mus., Copenhagen; Rijksmus., Leiden; BMNH, London; AMNH, New York; Mus. Nation. d’His. Nat., Paris; USNM, Washington, D.C.; Chicago Zool. Park, Brookfield; Lincoln Park Zoo, Chicago; Zool. Garten, Frankfurt; Bronx Zoo, New York; Brackenridge Zoo, San Antonio; San Diego Zoo, San Diego; Fleishhacker Zoo, San Francisco. Special thanks are due to Prof. U. Wolf, Director, Institute for Human Genetics and Anthropology, Freiburg, FRG, for providing the opportunity and encouragement to complete this work. The assistance of Dr. Philip Hershkovitz on questions of taxonomy is gratefully acknowledged. The editorial help of Kate Elias improved the text immensely. This study was supported in part by grants from the Wenner Gren Foundation (to H. 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