Publicaciones Geolo_gicas Especiales Del lngeominas

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ZONATION OF THE CRETACEOUS OF CENTRAL COLOMBIA BY AMMONITES 33 COMMENTS. This species resembles the inner whoda of Cheloniceraa (E.) debile Casey (1962, p. 244, pl. 37, r.a, 7, Text· Fig. 85, 86b and especially ftgums 86a. 86b) but on the EugUah species the central one of the branching ribs Is the 1trongest, turthennore It has "groups of tblee to four intermediary ribs at 20 mm diameter ,. (Casey, ibid..,p. 244) whereu in the Colombian species the intermediary ribs ue almost abeaent. Them Is also a resemblance between the Colombian specimen and the lectotype of the type species of the subgenus (Sinzow, 1906, pl. 2 Figs. lla-c; reproduced in Casey, 1962, p. 2S7, Text-Fig. 82a, b, c); on the Russian fonn the ventral median sulcus Is deep and the ven· tra1 tubercles prominent, opposite to the sltua· tlon the Colombian species. OCCURRENCE. Paja Fonnation (Arcillo· Utu abigarradu, segment E), and base of Ar· cllloUtu con nOdulos huecos. Upper Aptian. · · This SJ!ecies is named in honor of Mrs. El· vira de Borru, of Villa de Leiva. . Cheloniceras (Ef!.ic!JonJ2e.L camachoi n. ap. PI. 2, Fig. 3; Text-Fig. 4T. 1928 Cheloniceras stoliczkanum Gabb, Buse, p.141, pl.S, Fig. 2. Text-Fig.18. non 1936 Ch.[eloniceras] Stoliczkanum Gabb, ' Basse, p. 88. 'l 1936 Cheloniceras ct. Stoliczkanum Gabb sp. em. Basse, Breistroffer, p. 156. 1938 Cheloniceras stoliczkanum Gabb, An· derson, P..· 176, pars., only reference to Basse s illustrated specimen. 1964 Cheloniceras stoliczkanum (Gabb ), Etayo-Sema, pars., p. 118. 1968 Cheloniceras (Epicheloniceras)stoliczkanum sensu Basse (non Gabb ), Eta· yo-8ema, p.28, Fig. 3, Table I. 1970 Cheloniceras (Epich. [ eloniceras V sto· liczkanum, Wiedmann, p. 484, ex re· view of Etayo-Sema's 1968 paper. H olotype. (U.N.C.M.H.N.C.P.Ht.N.19). . . Paratype. (U.N.C.M.H.N.C.P.Pt.N.18). The adapical portion of the last preserved whod on the holotype (VI-10-17) shows strong ular ribs which bear a tiny mammtfcnn tu· bercle at the umbilical margin, a conical tuber· cle abot the middle of the flank and a promi· nent triangular transversely elongated :reriven tral tubercle; on venter the intercostal :iistance 1 1 • 1 more than twice the width of the ribs but it is ..· . • th. an . . two times on the flanks; in gener 1 the ..&tercostal spaces Qre shallow. The ribs are tnick an.d rounded. Between two prominent ribs a nearly imperceptible Intercalary rib appean, tt Ia feebly depressed along the ventral median line; with the tncreuing size the strength of both ribs and tuberculation rapidly increases, and approaching the preserved apertural region the Intercostal spaces are very deep and channel fonn; at this stage of growth the Intercalary rib approximates to the periumbUlcal tubercle of the preceding rib u if arising from t. · The periventral tubercles give the impression of being slightly bent posteriorly. There are 18 well defined ribs on the last whorl. The Jatenl tubercles were long and spinose as shown by depressions on the umbilical wall of the holotype and the paratype. DIAGNOSIS. This species is characterized by: A) the rapid on to genetic strengthening of Ita ornament contemporaneously with a slow in· crease of the umbilical diameter, B) ita subrectangular intercostal whorl section, with greatest width about the umbilical rim', and C) the regular occurence of only one intercalary rib appearing near the umbilical rim . Meuuremenw. D Euw H W DfEuw % DJH % VI · 10 • 17 47 21 19 28 411· 40 T.I.P. GuaduQ 61 27 ? ? . 44 1 COMMENTS. This species differs fonn Cheloniceras stoliczkanum (Gabb )(1869) by not having the very depre!l&ed whorl section during ita development and the width-length ratio not remaining the same throughout as on the bolo· type of the California species (Acad. Nat. Sci. Phil., no. 4 786). The ventral nodes on Gabb's species are broadly rounded, lobe-like, but in the Colombian species their height is greater than their width (in correlation with the com· pression of the section?); the periumbilical tu· bercles are represented by feeble bullae through the ontogeny on Gabb's species but they are co nical and prominent early in the ontogeny of the Colombian species. OCCURRENCE. Socota Member. Upper Aptian. Paja Fonnation (Arcillolitu ablgarradas, Segment E). Upper Aptian. This species Is named in honor of geologist Ricardo Camacho. 1906 Douuilleiceras Stoliczkanum, Gabb, R. Douville, p. 145 (pars), only pl. 1, Fig. 1, la. 1925 Douuilleicera.s AmazonarumBurckhardt, p. 26. 1938 Douvilleiceras stoliczkanum Gabb, Anderson, p. 176, p. Holotype. Specimen figured in Douville's paper; see synonym.
34 F. ETA YO · SERNA Hypotype. (U.N.C.M.H.N.C.P. Hy. N.5). Type locality. "Vallee des Amazones .. [sic], un· known. Descn· tion after the only specimen avai· lable [C-514 . This is a moderately evolute species; the oral portion of the penultimate whorl is characterized by widely separated, rela· tively thin primary ribs three to four times na· rrower than tlle intercostal spaces; they bear a mammtfonn tubercle at the umbilical rim, and a prominent spine at center of the flank. On the adapicai portion of the last preserved whorl, the ribs appear to be extended towards the umbill· cal seam, with a feeble adoral concave arc; on the inner flank the ribs are nearly radial but on the adventral half of the flank and on venter they swing slightly forward producing a wide adoral arc; the growth lines are rme raised threads which sometimes gather in bundles and resemble intercalary ribs but no true intercalary ribs are present. All ribs are depreued along the ventral median line and on both sides of it pro minent crest like tubercles are developed. On the adoral portion of the last whorl the ribs are only slightly promiradiate. No living cham· ber is preserved; up to the anterionnost part of the preserved conch it is septate. The whorl sec· tion at this point ia inflated, rentfonn, it has an Inclined J:llbilical wall which rounds &mootbly into the flanks. DIAGNOSIS. This species is characterized by: A) its sparse ribbing with only primary ribs or sporadic, weak intercalary ribs that disappear before reaching the umbilical rim, and B) its re· nifonn whorl &ectlon. MeUUftlmenta. D Euw H W D/Euw % D/H% C-614 80 30 20 83 ISO 33 COMMENTS. This is a peculiar species not easily comparable to any described specie& known to me; it is most aimllar to "Douuilleice· ras Martini d'Orb." as described by Sinzow (1907, p. 171, pl. 2, especially fig. 13a, 13b) but on the Russian species the intercalary ribs are common and at simllar dlamete:n when rlbbinll: is attenuated in the Russian species the o_p pOSlte seema true for the Colombian Wton. The generic •ignment is questioned because of the projection of the ribs onto venter on the Jut whorl. OC9URRENCE. Socota Member. Upper Aptian. Chlon f&12.f!eloni£erus r _o'SaQL: n. sp. PI.2, Fgs. 9·10; Text-Figs. 4R, 48; 11. Holotype. C·223 (U.N.C.M.H.N.C.P.Ht. N.20). Paratype. C-223 (U. N. C. M. H. N. C. P. Pt. N.19, 20, 21). A) Up to 25 mm D [ C-223·11. The umbi· liens is deep· and wide; on· the two im t observa· ble whorls the sculpture can not be clearly dla· cemed but at the beglnlng of the third whorl (4th of the phragmocone?), very prominent elongated spinose tubercles develop on the mid· die of the flank (= along the involution line), they arise from low wide ribs which extend toward the umbilical rim. On the fourth or last preserved whorl of this specimen very slight mammiform tubercles develop at the periumbi· lical inception of the ribs; at the same time on both sides of the ventral median line, rounded to acute swellings are developed. Although the ribs tend to fonn a wide concave arc on the fianks and to project weakly onto the venter they also tend to widen on the adumbilical half of the whorl as if forming an adoral arc 1 at the same time they tend to split longituainally. Along the ventral median Une the ribs are de· pressed; sporadically there is an intercalary rib which differs from the primary ribs only in its lesser strength. The whorl section is subcompressed to subpoligonal: the umbilical wall is inclined, it merges smoothly into the slightly convex adumbllieal half of the flank, the adventral half of tl1e flank converges and rounds into the flatte· ned venter. B) Up to 35 nun D [C-223-2). The earliest part of the last whorl of this specimen is like · the late part of the preceding specimen. The ornament continues developping _ in a similar. way except that one or two folds (In tercalatory ribs?) without tubercles appear between two primary ribs. The periumbilical tubercles conti· nue inconspicuous but the ventral tubercles tend to acoontuate; the ribs tend to extend to the umbilical seam fanning and acute adoral concavity. C) Up to 50 mm D [C-223·11]. At the beginning of the last whorl in this specunen the distance between the centrolateral and periven· tral tubercles progreuively increases. At this stage the intercalary ribs are well defined and characterized by lack of periumbilical or lateral tubercles, they have only periventral tubercles; this intercalary rib appears near the preceding primary and approaches it near the umbUlcal margin. The last two ribs of this specimen chan· ge their strong lateral tubercles into tiny spines. 'Ibe Intercostal whorl section ilaubrectangular, it has an oblique umblllcal wall which tends to become vertical toward the umbilical seam. The ventral zone is nattened. Near the aperture the ribs give the lmpression of slightly curved clubs. D) Up to 75 mm D (C-223]. The oma· ment is u on the preceding specimen; the living chamber represents two thl.rda of the last whorl; the principal morphological features are the progresaive weakening of the tubercles, especla· lly the centroiateral and ventrolateral onea, which cwaes the ribs to loose their ventral median depression. 'Ibe adaperturalmoat whorl section is a slightJ.y depresaed dome. . DIAGNOSIS. Thia apeclea is characterized by: A) the ontogenetic development of the no des whose strength lncreaaes from mammiform adumbilica! ones to the pertventral comute tu· !.'lerdes which in intennediate stages of growth
Page 1 and 2: Publicaciones Geolo_gicas Especiale
Page 3 and 4: PUBLICACIONES GEOLOGICAS ESPECIALES
Page 5 and 6: CONTENTS ABSTRACT . . . . .. . . .
Page 7 and 8: Pl ate 4. Plate 6. Plate 6. Plate 7
Page 9 and 10: 2 F. ETA YO· SERNA The materials t
Page 11 and 12: 4 F. ETA YO· SERNA PHYSICAL STRATI
Page 13 and 14: FIGLH 1\ 2 2AJ Vl:LLA DE LEIVA CD -
Page 15 and 16: 8 Gloriaceras paulinae n. sp. Zumpa
Page 17 and 18: 10 F. ETA YO -SERNA coarse grained
Page 19 and 20: 12 F. ETA YO · SERNA trated in sev
Page 21 and 22: 14 F. ETA YO · SERNA ated. In the
Page 23 and 24: 16 F. ETA YO · SERNA TABLE I ASSEM
Page 25 and 26: 18 F. ETA YO ·SERNA tion consisfli
Page 27 and 28: 20 F. ETA YO ·SERNA increasing ove
Page 29 and 30: 22 has a subelliptical to subcircul
Page 31 and 32: 24 F. ETAYO ·SERNA rounds abruptly
Page 33 and 34: 26 F. ETAYO · SERNA ffer, 1963, p.
Page 35 and 36: 28 F. ETA YO - SERNA this is partic
Page 37 and 38: 30 F. ETAYO ·SERNA and bifurcate;
Page 39: 32 F. ETA YO · SERNA thirds of the
Page 43 and 44: 36 F. ETA YO - SERN A tuberculation
Page 45 and 46: 38 F. ETAYO - SERNA they project sl
Page 47 and 48: 40 last whorl the ribs are inconspi
Page 49 and 50: 42 Hypacanthoplites dognaliciae n.
Page 51 and 52: 44 F. ETA YO · SERNA One large spe
Page 53 and 54: 46 F. ETAYO - SERNA "Acanthoplites
Page 55 and 56: 48 F. ETA YO · ERNA These tubercle
Page 57 and 58: 50 .,CQ.IQmQ.ik.er::fJ§. W forg.ro
Page 59 and 60: 52 Among the subsequent flared ribs
Page 61 and 62: ZONATION OF THE CRETACEOUS OF CENTR
Page 65 and 66: zoNATION OF THE CRETACEOUS OF CENTR
Page 71 and 72: ? ? ZONATION OF THE CRETACEOUS OF C
Page 91 and 92:
86 F. ETA YO - SERNA rent localitie
Page 93 and 94:
88 The adapical end of this conch h
Page 95 and 96:
90 F. ETAYO · SERNA dies out near
Page 97 and 98:
92 OCCURRENCE. La Frontera Fonnatio
Page 99 and 100:
94 re is an asymmetrical sulcus bor
Page 101 and 102:
96 (1898, p. 198, figs. 23a,b,c), w
Page 103 and 104:
98 the flank and have a periventral
Page 105 and 106:
100 F. ETA YO - SERNA On the adapic
Page 107 and 108:
102 ventral third of the whorl side
Page 109 and 110:
104 but "Fundort: Von Stiibel im Be
Page 111 and 112:
106 F. ETA YO · SERNA En dos regio
Page 113 and 114:
108 In due regioni della Cordiglier
Page 115 and 116:
110 REFERENCES ANDERSON, F. M. 1938
Page 117 and 118:
112 -- 1963.- Atlas des fossiles ca
Page 119 and 120:
114 KARSTEN, H. 1858.- Vber die geo
Page 121 and 122:
116 Colon. Geol. min. Resourc., uol
Page 123 and 124:
118 F. ETA YO • SERNA WIEDMANN, J
Page 125:
120 A) B) C) D) E) F) G) H) I) L) M
Page 129:
124 F. ETA YO • SERNA A) B) C) D)
Page 133 and 134:
FIGURA 7 A Q 8 ) / ! E I c K FIGUR
Page 136 and 137:
132. A) B) C) D) E) F) G) H) I) J)
Page 138 and 139:
134 Scatter diagram of the distribu
Page 140 and 141:
136 Scatter diagram of the relation
Page 142 and 143:
Page 144 and 145:
140 F. ETA YO · SERNA Scatter diag
Page 146 and 147:
Page 148 and 149:
144 F, ETAYO ·SERNA Scatter diagra
Page 150 and 151:
146 F. ETA YO · SERNA FIGURE 16 Sc
Page 152 and 153:
148 F. ETA YO · SERNA Scatter diag
Page 154 and 155:
PLATES 1-15
Page 157:
154 F. ETA YO · SERNA Fig. 1) Chel
Page 161:
158 F. ETA YO · SERN A PLATE 4 Fig
Page 165:
162 Fig. 1) Vectisites (Zambranoite
Page 169:
166 F. ETA YO · SERNA Fig. 1) Eodo
Page 173:
170 Fig. 1) Carloscaceresiceras cac
Page 179:
176 Fig. 1) Fig. 2) Fig. 3) Fig. 4)
Page 183:
180 Fig.1) Codaziceras scheibei (Ri
Page 186 and 187:
184 Engonoceras, 74. duartci, n. sp
Page 188:
186 Tegoceras, 82. benavidescaceres
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