Haploceras staszycii (Zeuschner, 1846)

Pandey, Dhirendra Kumar, Fuersich, Franz T., Alberti, Matthias, Das, Ranajit & Saez, Federico Oloriz, 2022, First population-level study of the ammonite genus Hildoglochiceras Spath, and the Lower Tithonian record of the Hildoglochiceras Horizon in the Kachchh Basin, India, Zitteliana 96, pp. 1-49 : 1

Haploceras staszycii (Zeuschner, 1846)

Fig. 6A-G, L-N

Ammonites staszycii sp. nov., 1846 - Zeuschner: pl. 4, fig. 3.

Ammonites elimatus sp. nov., 1865 - Oppel: 549.

Haploceras elimatum (Oppel), 1868 - Zittel: 79, pl. 13, figs 1-7.

Haploceras deplanatum sp. nov., 1875 - Waagen: 44, pl. 11, fig. 9a, b.

Haploceras elimatum (Oppel), 1960 - Collignon: pl. 142, figs 536, 537.

Glochiceras deplanatum (Waagen), 1960 - Collignon: pl. 142, figs 540-542.

Material.

Seven specimens, Hildoglochiceras Bed of Jara Dome (Lower Tithonian); KSKV2019Jara/61, 62, 63, 64, 66 (all figured), 68, 69 (figured).

Description.

Shell incomplete, compressed, involute with oval whorl section, moderately distinct to distinct umbilical shoulder, short and slightly arched umbilical wall. Maximum thickness of the shell is either at mid-lateral height or slightly below it. Height and thickness ratios with respect to diameter show variation. Suture lines preserved, densely frilled with most pronounced second lateral saddle, appears getting crowded anteriorly.

Remarks.

The specimens represent only parts of phragmocones and show erosional external surfaces. The ornamentation is not preserved in the present specimens. They appear smooth, as is typical for inner casts. However, parts of the siphuncle are well preserved. In two of the specimens (KSKV2019Jara/63 and 64) small portions of shell are preserved, also indicating a smooth external surface. The largest specimen (KSKV2019Jara/61) measured in the present collection has a diameter of ca. 53 mm and the crowding of the last septa indicates that it has attained the adult size. At a given diameter, the diameter of umbilicus may be larger but in general, the morphological features such as the shape of the shell, whorl section, suture lines and dimensional proportions match Haploceras elimatum (Oppel) ( Collignon 1960: pl. 142, figs 536, 537) recorded from the Hildoglochiceras kobelli Zone of Madagascar (Early Tithonian) with a shell and ventral region clearly wider than in Oppel’s (1868) type. West-Tethyan Haploceras elimatum (Oppel) show more convergent, less inflated flanks, hence their “clear” separation from Haploceras staszycii (Zeuschner). Zeuschner (1846, pl. 4, fig. 3) did not give a scale with his figure. Zittel (1868: 81) mentioned a close morphologic similarity between H. elimatum of Oppel and H. staszycii of Zeuschner and stated that the specimen illustrated in Zeuschner (1846) is rather large ( Zittel 1868: "ein ziemlich grosses Exemplar") showing a smaller umbilicus and a wider shell than H. elimatum . Zittel’s (1870) description of H. staszycii (Zeuschner) was based on 300 specimens gathered from Rogoznik, Maruszina, central Apennines, and Bavaria. Zittel highlighted the shell-width and flattened flanks as distinguishing features to separate H. staszycii (Zeuschner) from H. elimatum (Oppel), although, he found difficulty in separating the young specimens of the two species. Zittel also made a rather uncommon observation about the occurrence of a keel-like elevation on the venter in the inner whorls up to 30 mm in shell size, but no further author mentioned this feature. If all the dimensional proportions of the specimens of H. staszycii (Zeuschner) and H. elimatum (Oppel), which are available (see Table 1 ) together with those of Zeuschner’s collection (300 specimens), croweding of septa in the largest phragmocone in the present collection and the figures of both the species illustrated by earlier workers are reviewed, there is a good possibility that H. staszycii (Zeuschner) represents the microconch whereas H. elimatum (Oppel) represents the marcoconch of the same species.

Haploceras subelimatum Fontannes ( Collignon 1960: fig. 538) differs from Haploceras elimatum (Oppel) ( Collignon 1960: pl. 142, figs 536, 537) in having a finer ornamentation, while the type of Haploceras subelimatum in Fontannes (1879: 12, pl. 2, figs 5-6) shows a more compressed shell, and a general glochiceratin-like aspect. However, dimensional proportions are within the range of variation as seen in the specimens of the present collection (Fig. 7 , also see table of dimensions). In the Stramberger specimen described by Oppel (1865: 549), the body chamber including the peristome is preserved. It measures 125 mm in diameter. The shell is either smooth or covered with fine curved growth lines.

Haploceras deplanatum Waagen (1875: 44, pl. 11, fig. 9a, b; Collignon 1960: pl. 142, figs 540-542) shows a similar H/T ratio (1.33-1.75) and U/D ratio (17-22) to the present specimens, however, Waagen’s specimen (1875) shows a more flattened shell, while the specimen of Madagascar ( Collignon 1960, pl. 142, fig. 542) has a thicker whorl section at the corresponding diameters. If all the specimens described by Waagen and Collignon belong to the same species, then apparently there is a large range of variation in the H/T ratio (Fig. 7 ). In fact, later authors denied a conspecifity, and raised doubts about the interpretation of the Waagen type as Haploceras or Glochiceras given the absence of the peristome (e.g., Ziegler 1958). Waagen (1875) mentioned that the umbilical edge is not distinct. In contrast to his description which includes arched lateral surfaces and a steep slope of the umbilical wall. In the present specimens, the umbilical shoulder is moderately distinct, like in the specimens from Madagascar.

Furthermore, Collignon (1960: pl. 142, figs 540-542) assigned H. deplanatum to Glochiceras , because of their small size, but in the specimens figured by Collignon, there is no indication of a lateral groove and opening of the shell, which should have been visible at that diameter. In fact, his specimens are incomplete. Secondly, Glochiceras s. str. ranges from the Oxfordian to Kimmeridgian ( Arkell et al. 1957: L274), but a single specimen was reported from the Lower Tithonian in Neuburg ( Barthel 1962), and the records of Glochiceras reported by Collignon (1960) from the assumed Early Tithonian Hildoglochiceras kobelli Zone of Madagascar need confirmation.

Biostratigraphy.

Haploceras staszycii (Zeuschner) is a long-ranging species from the Upper Kimmeridgian to Tithonian and Lower Berriasian horizons elsewhere. The available data across the northern and eastern margins of the Trans-Erythraean Trough, indicate that Haploceras s.str. is a rare genus from the Spiti Shales. Spath ( 1928) assumed that Uhlig (1903) reported only a single example of Haploceras s. str., which is correct in the case of Haploceras indicum Uhlig, 1903 (coll. Diener, middle division of the Spiti Shales in Chojan), a form morphologically close to the Tithonian type of Haploceras staszycii (Zeuschner), or a local variant of this taxon. Yin and Énay (2004) reported and illustrated Haploceras sp. from a Lower Tithonian Uhligites - Aulacosphinctoides Assemblage in the Tibetan Himalayas, and envisaged that it resembles H. caractheis Zeuschner, the nominal species of reference for Énay and Cecca (1986). However, this cannot be evaluated from the illustration provided by Yin and Énay, while the occurrence of Haploceras from the Tibetan Himalayas was not confirmed by Énay (2009).

In southern Pakistan, Fatmi and Zeiss (1994) reported (without illustration) Haploceras cf. elimatum (Oppel) and Haploceras sp. from Upper Tithonian strata from the Chakkary/Draber and Phai sections, together with himalayitins or even above, in their "third fossil horizon" that may include some reworked ammonites. From Jaisalmer, Pandey and Krishna (2002) reported upper Lower Tithonian Haploceras together with Hildoglochiceras from their Communis Zone, and Krishna (2017) used records of the long-ranging genus Haploceras from Jaisalmer and Pakistan to interpret a mid-Early Tithonian age for the Natricoides Zone.

Waagen (1875) reported some species of Haploceras from Kachchh, but used this genus in a broader sense than it is used today, and applying it to forms from horizons most probably older than those typical for this genus. His Haploceras deplanatum does not belong to this genus, and his Haploceras propinquum collected from the lowest beds of the Katrol Group (= Jhuran Formation) "immediately above the oolite with Asp. perarmatum ", on the south side of Keera Hill near Charee, could refer to his Middle Kimmeridgian (i.e. to the Eudoxus-Steraspis stratigraphic interval according to Spath 1933) hence pointing to an extended lower range for Haploceras into the Kimmeridgian or, alternatively, to a large local stratigraphic gap if the taxonomic reinterpretation made by Spath ( 1928) applies. However, this latter interpretation at the genus level, recently assumed by Énay (2009), raises the need for a revision of the morphologic features typical of Haploceras . Spath (1924) recognized one example of Haploceras (= Glochiceras ?) in the Blake collection, but no examples of Haploceras deplanatum Lemoine (non Waagen?) sp. (= Glochiceras cf. Spath, 1928), which were commonly reported from Madagascar. Further Spath ( 1927: 6) identified abundant specimens of Haploceras elimatum (Oppel) included in an assemblage with belemnitids in the Andranosamonta Marls. He explained the scarcity of Haploceras in Kachchh due to the commonly occurring discontinuous sedimentary succession ( Spath 1924, 1927). Nevertheless, there is a record of a Haploceras and Virgatosphinctes association within the Umia Group (= Jhuran Formation) (compare Spath 1927: 14). Spath ( 1928) reinterpreted the species Haploceras deplanatum Waagen with a lateral groove of variable depth as Glochiceras from the Middle Kimmeridgian (Beckeri Zone), and some of Waagen’s (1875) species of Haploceras ( H. deplanatum and H. propinquum ) as forms transient from Middle Kimmeridgian Glochiceras of the G. fialar group to the genus Hildoglochiceras , respectively. Spath ( 1928) described a single Haploceras sp. close to a juvenile H. elimatum (Oppel) from the Upper Tithonian (Transitorius Zone?) of the Umia Group (= Jhuran Formation). He envisaged recurrent homeomorphism in long-ranging haploceratins, which he interpreted as inhabitants of warm waters, and highlighted that the smooth inner whorls of the common Taramelliceras of the T. kachense group from the Middle Kimmeridgian (Eudoxus and Beckeri? zones) with ventral reliefs resemble Haploceras charactheis Zeuschner. Spath ( 1931) mentioned earlier revisions of the single specimen of Haploceras propinquum Waagen, regarded it as a form probably transient to Hildoglochiceras (Spath, 1928), and later reinterpreted it as Hildoglochiceras (Spath, 1933). Spath ( 1928) reinterpreted Haploceras propinquum Waagen and Haploceras dieneri Waagen as Hildoglochiceras , and Haploceras cf. tomephorum Zittel to be a juvenile aspidoceratin. This author identified the Haploceras beds of Gudjinsir as the base of his Portlandian, with several species assigned to Hildoglochiceras , recognized Haploceras elimatum (Oppel) as the most common component in the Gudjinsir fauna of Kachchh, and among Kachchh species of Alpine-Mediterranean affinity, and described Haploceras sp. ind. juv. from his Tithonian Umia beds. Pandey et al. (2016) cited Haploceras cf. tomephorum Zittel among Upper Tithonian ammonites reported from the Kachchh Basin by earlier workers. Krishna (2017) reported Haploceras cf. elimatum (Oppel) from his Natricoides Zone-Communis Zone, Communis Subzone, which he interpreted as corresponding to a 3rd-order sequence with MFS in the Krafti Subzone, and correlated the Natricoides Zone with the Semiforme/Verruciferum Zone in Europe. Krishna identified the same stratigraphic interval and 3rd-order sequence in Jaisalmer.

In Madagascar, Lemoine ( 1910) refused to use the taxon-name Haploceras and reported abundant specimens of Lissoceras deplanatum (Waagen), which he clearly distinguished from Haploceras elimatum (Oppel) and Haploceras staszycii (Zeuschner) and interpreted to be younger (Tithonian). This author did not illustrate his Madagascan Haploceras deplanatum , thus the equivalence with the type of Waagen cannot be evaluated. Spath (1925a) reinterpreted Lissoceras deplanatum (Lemoine non Waagen s.) as Haploceras elimatum (Oppel), illustrated from his Kimmeridgian horizons of Antsalova, which according to Lemoine shows some affinity with Haploceras indicum Uhlig (1903: 21, pl. 3, fig. 2a, b), a form that could be better interpreted as closer to Haploceras staszycii (Zeuschner). Spath (1925b) interpreted Haploceras elimatum (Oppel) as the most abundant ammonite in the undescribed collection from Madagascar, but had reservations concerning the high degree of similarity envisaged between ammonite faunas of Madagascar and Kachchh. Spath ( 1928) reconsidered the suture of his Haploceras elimatum (Oppel) from Madagascar ( Spath 1925a) as being closer to that shown by Sicilian specimens of Haploceras staszycii Zeuschner. Spath ( 1928) mentioned Haploceras elimatum (Oppel) from the Besaire Collection, and recognized its low value for precise age-interpretations given its long stratigraphic range, as well as its common occurrence with Hildoglochiceras kobelli and Hildoglochiceras latistrigatum at Antsalova. He also mentioned Haploceras staszycii (Zeuschner) from the same collection, recorded west of Mampikony, and highlighted the similarity among Madagascan ammonite assemblages and those known from Tendaguru (Tanzania), Kachchh, and Spiti. Collignon (1960) stressed the affinity of Tithonian faunas from Madagascar with those from Kachchh, Spiti, Kurdistan, SW Europe, and NW Africa, and described and illustrated diverse haploceratins from Lower Tithonian Kobelli Zone (Madagascar), including Haploceras gr. elimatum (Oppel) - Haploceras subelimatum Fontannes, and Haploceras staszycii (Zeuschner). This author also reported Glochiceras deplanatum Waagen, which he interpreted as inconclusively known and comparable to smooth inner whorls of the more evolute Hildoglochiceras , and difficult to distinguish from inner whorls of Haploceras elimatum , except for the suture line.

Southwards along the western margin of the Trans-Erythraean Trough, Howarth and Morris (1998) reported Haploceras stascyzii (Zeuschner) from a 5 m interval with Upper Kimmeridgian perisphinctins and taramelliceratins at Wadi Arus, southern Yemen, and interpreted their Kilya Member to represent the Upper Kimmeridgian Beckeri Zone to Lower Tithonian Hybonotum Zone, while their new species Haploceras umbilicatum was recorded together with probable uppermost Tithonian to Lower Berriasian ammonites. No Haploceras were reported by Zeiss (1971, 1984) from Ethiopia, and no reports are available from Somalia. In Kenya, Haploceras seems to be absent ( Beyrich 1877), or it was rare, because Haploceras elimatum (Oppel) early on recorded further south from the Trigonia smeei Beds at Tendaguru, Tanzania ( Zwierczyki 1914), was interpreted as Lissoceras ( Dietrich 1925, 1933; Spath 1925a, 1933; Bussert et al. 2009). Kapilima (2003) too did not report Haploceras from Tanzania.

Based on the preceding revision, the record of Haploceras staszycii (Zeuschner) - Haploceras elimatum (Oppel) from the Hildoglochiceras kobelli Zone of Madagascar (Early Tithonian of Collignon 1960) cannot be used for a conclusive, regional age-interpretation in the Trans-Erythraean Trough, where its precise stratigraphy is unknown. However, the described specimens are interpreted to represent Lower Tithonian (three-fold division) horizons in accordance with the biostratigraphic interpretation of the here described Hildoglochiceras , a single specimen of Aulacosphinctoides and an incomplete virgatosphinctin.

Figures

Figure 6. A-G, L-N. Haploceras staszycii (Zeuschner, 1846). A. KSKV 2019 Jara / 63, left side view of phragmocone, note well preserved suture lines; B, C. KSKV 2019 Jara / 64; B. Left side view of phragmocone; C. Apertural view showing broken aperture along a septum; D. KSKV 2019 Jara / 66, apertural view; E. KSKV 2019 Jara / 69, apertural view showing broken surface along a septum; F, G. KSKV 2019 Jara / 62; F. Left side view of phragmocone, note well preserved suture lines; G. Apertural view; L-N. KSKV 2019 Jara / 61; L. Right side view of phragmocone; M. Apertural view; N. Outline of whorl-section; H-K, O. Haploceras sp.; H, O. KSKV 2019 Jara / 65; H. Apertural view along a broken surface of phragmocone; O. Right side view showing phragmocone and a part of body chamber; I-K. KSKV 2019 Jara / 67; I. Vental view; J. Apertural view; K. Left side view of body chamber; P-T. Hildoglochiceras kobelliforme (Bonarelli, 1894) (m); P-S. KSKV 2019 Jara / 1, inner cast with epigenized shell preserved; P. Right side view of moderately evolute specimen (U ≈ H), with subtle uncoiled outer whorl (probable adult), body chamber 180 ° with peristomal vestige (dorsal branch on inner cast?); Q. Suture lines at the end of phragmocone, note increased density at the end of phragmocone; R. Apertural view, note epigenized shell clearly identifiable on the ventral region; S. Oval whorl section with narrow venter, wide lateral groove on the body chamber; T. KSKV 2019 Jara / 2. inner cast, left-side view of nearly complete adult specimen with clear final uncoiling, partial preservation of epigenized shell, ca. 180 ° of preserved body chamber on inner cast of comparatively fine-to-medium sandstone.

Figure 7. Scatter plot showing D: H / T ratios of some related species of Haploceras.