SYSTEMATIC PALEONTOLOGY

Order BELEMNITIDA von Zittel, 1895
Suborder BELEMNITINA von Zittel, 1895
Family PASSALOTEUTHIDIDAE Naef, 1922
Subfamily MEGATEUTHIDINAE Sachs and Nalnjaeva, 1967
Genus BREVIBELUS Doyle, 1992 (= Brachybelus)
(Figure 5)

Type species.- Belemnites breviformis Voltz, 1830. Toarcian-Aalenian.

Diagnosis. Guard small, short, and robust. Outline symmetrical and conical to cylindroconical, profile nearly symmetrical, otherwise similar to outline. Apex obtuse to moderately acute, often mucronate. Venter inflated in some species. Transverse sections quadrate, compressed in some species, depressed in others. Apex devoid of grooves or striae. Lateral lines may be well developed, consisting of two weak parallel depressions separated by a well-developed ridge. The phragmocone is ventrally displaced, penetrating about one half of guard. Apical angle c.27° (from Doyle 1992).

aff. Brevibelus sp.
(Figure 5.1-5.4)

Material. Three partial latex casts, UTGD87331c, 87320c, 87335b, Locality Q10. Most data is from 87331c, details of apical region from 87320c and 87335b.

Description. Guard small, conical, short, robust, laterally compressed, length c. 3 times maximum diameter. Largest specimen (Figure 5.1) 42 mm long, with an estimated 10 mm of the apical region missing. It forms the basis of most of this description. Other specimens are short apical fragments. Widest point on guard anteriorly placed; maximum dorsoventral diameter 14.3 mm, lateral diameter 11.5 mm. Outline symmetrical, weakly conical, widest point at anterior, sides taper regularly towards the apex, more rapidly over terminal 10 mm. Profile asymmetric, more conical than outline. Dorsal surface inflated near mid-guard, apical half of the guard curves more rapidly towards apex. Ventral surface almost straight, not inflated. Cross sections compressed throughout length of guard. Dorsal and ventral surfaces rounded, lateral surfaces more flattened. Lateral lines present near the midline of the guard, preserved as a single wide depression parallel to the ventral surface; visible in the alveolar region, missing over c. 12 mm at mid-guard, then continues towards the apex. Missing section is possibly an artefact of the casting process, or a result of damage to the mould. Alveolus laterally compressed and deep, penetrating the guard for an estimated 25–30 mm.

Discussion. The specimens are broadly similar to Bathonian specimens from New Caledonia illustrated as Belemnitidae (= Passaloteuthididae) gen. et. sp. nov (Challinor and Grant-Mackie 1989) and to New Zealand Brevibelus (Toarcian) currently under study.

Range. Latest early Bajocian (detailed discussion on inferred age follows taxonomy section).

Suborder BELEMNOPSEINA Jeletzsky, 1965
Family BELEMNOPSEIDAE Naef, 1922
Genus BELEMNOPSIS Bayle, 1878
(Figure 5)

Type species.- Belemnites bessinus d`Orbigny, 1842. Bathonian.

Remarks. Riegraf (1999) argues that the genus Belemnopsis Bayle 1878 is invalid on forensic grounds, and that the name should be replaced. The argument for replacement is not accepted here.

Diagnosis. Guard moderately elongate and robust, to short and very robust, c. 100 mm long and c. 12-15 mm in maximum diameter; larger and smaller forms known. Cross section at mid-guard and apical region usually depressed, equi-dimensional to compressed anteriorly. Median ventral groove strongly developed, usually extends nearly to the apex, shorter in some taxa. Alveolus short in relation to guard length. Double lateral lines are present, often poorly developed, but more prominent in pre-adult forms. Developmental sequence includes a slender, sometimes strongly hastate, juvenile to early immature guard (our concept).

Belemnopsis cf. B. stevensi Challinor, 1974
(Figure 5.7-5.10)

cf. 1965 Belemnopsis alfurica Stevens, pl. 5, figures 10-12 only.
cf. 1965 Belemnopsis keari Stevens, pl. 3, figures 7-9; pl. 4, figures 1-3 only.
cf. 1974 Belemnopsis stevensi Challinor, figures 8-13.
cf. 1979 Belemnopsis maccrawi Challinor, figures 22-42.
cf. 2003 Belemnopsis stevensi Challinor p. 87, figures 6-20, p. 88, figures 21-36.

Material. Three latex casts and a damaged calcareous specimen. R.7517.16.1 (cast, Figure 5.7), a complete immature guard, ventral surface exposed; R.7517.21.2 (Figure 5.8), a damaged immature calcareous specimen; R.7504.3.9 (cast, Figure 5.9), a juvenile almost complete guard with anterior region missing; R.7519.5.20, (cast, Figure 5.10), a stem fragment of an immature guard (apical region missing, one flank and ventral surface exposed.

Description. Guard elongate, slender to moderately slender. Outline hastate, widest point near mid-guard. Apical region moderately elongate, apex central. Flanks converge anteriorly to produce moderate hastation; anterior flanks usually slightly curved, sometimes straight but converging. Profile similar to outline but apparently less hastate. Cross section uncertain but probably equi-dimensional or depressed. Ventral groove extends almost to apex, moderately wide and deep, very wide and deep in Figure 5.10.

Discussion. Heterian Belemnopsis appear near the base of the stage and extend to the top. Belemnopsis annae, B. stevensi and B. keari appear in succession and are stratigraphically separated, except for a short concurrent range zone of B. stevensi and B. keari in the latest Heterian (Challinor 1979, figure 2). Adults of all three can be recognised by differences in size, hastation, or apical line position. Juvenile and adolescent guards are difficult to differentiate (cf. Challinor 1979, figures 14, 29, 50). All three Heterian taxa were originally included in Belemnopsis keari (Stevens 1965). Later work based on new collections and statistical data demonstrated that three different taxa were present (Challinor 1979). The three taxa are collectively referred to later in this paper as the B. stevensi group.

Based on their small size and shape we interpret the Latady Group Belemnopsis cf. B. stevensi as immature specimens. The figured specimens (Figure 5.7-5.10) closely resemble the Heterian juvenile and adolescent specimens cited above (note scale of all figured specimens). R.7517.21.2 (Figure 5.8) is a damaged calcareous specimen partly enclosed in matrix (and possibly figured with the apical end uppermost). R.7504.3.9 and R.7519.5.20 (Figure 5.9–5.10, respectively) are very strongly grooved. The latter resembles a particularly strongly grooved Heterian specimen (cf. Challinor 2003, figures 24, 25).

Mutterlose (1986) described Belemnopsis aff. keari from his locality 8 (Bean Peaks Orville Coast) c. 15 km northeast of R.7508. The adult specimen (Mutterlose 1986, figures 6a, b) strongly resembles some adult specimens of B. stevensi in size, outline and profile (cf. Challinor 2003, figures 10, 11, 13, 14, 18), but to judge from figure 6a, b, is more depressed in cross section than most (although apparently within the range of variation). The other specimen (figure 6c, d) is a fragment of a juvenile. Mutterlose (1986) considered B. aff. keari to be Kimmeridgian in age; the approximate stratigraphic position of his specimens is indicated in Figure 7 by M3. Belemnopsis aff. stevensi appears slightly earlier in Ellsworth Land than does the B. stevensi group in New Zealand.

Range. Early Callovian – middle Kimmeridgian.

Belemnopsis sp. A
(Figure 5.11)

Material. One latex cast (UTGD87353c, Locality Q13), of the apical region of an adult guard.

Description. Fragment 34 mm long; flanks, dorsal, and ventral surfaces curve smoothly towards the centrally placed apex, more rapidly over the terminal 10 mm. Apical region moderately obtuse. Diameters 12.5 mm lateral, 12 mm sagittal; cross section depressed near anterior end. Ventral groove very wide and shallow, terminating almost at the apex.

Discussion. The fragment is similar in outline and groove termination position to many New Zealand and Indonesian Upper Jurassic Belemnopsis, although its wide shallow posterior groove is atypical. Groove morphology is similar to those of Belemnopsis gladiatoris and B. alexandri, Berriasian taxa described from Alexander Island, West Antarctica, by Willey (1973).

Range. Middle Callovian – early Kimmeridgian.

Belemnopsis sp. B
(Figure 5.12-5.13)

Material. Two latex casts, UTGD87162b, locality Q2, is a fragment, apparently of the posterior stem and anterior apical region. R.7504.3.146 is the anterior half of a pre-adult guard, possibly including part of the alveolar region.

Description. R.7504.3.146 (Figure 5.12) c. 50 mm long, transversely hastate (posterior diameter c. 9 mm, anterior diameter c. 7.5 mm), slightly sagittally hastate, and cross section is depressed. Ventral groove moderately wide and deep, terminates suddenly, apparently about halfway down the guard. UTGD87162b (Figure 5.13) c. 33 mm long, c. 17 mm in transverse diameter, 16 mm sagittal, cross section depressed. Ventral groove wide, moderately deep, terminates suddenly at mid-fragment.

Discussion. Assuming the two specimens are conspecific, R.7504.3.146 is a pre-adult guard. The ventral groove in some specimens of Belemnopsis sikilyensis (Middle Oxfordian, Madagascar, Combémorel 1988) terminates in a similar manner to that of these specimens.

Range. Latest early Oxfordian – early Kimmeridgian.

Belemnopsis sp. C
(Figure 5.14-5.15)

Material. Four latex casts (R.7507.7.19, R.7519.4.a, b, R.7519.26.4) of complete specimens. All are juvenile guards. Description based mostly on R.7519.4.3a which lies on a bedding plane with a ventrolateral surface uppermost. Most of the ventral surface and part of one flank is visible.

Description. Very small, slender, hastate, (?early juvenile) guard, 32 mm long and c. 2 mm maximum diameter. Widest point 12–14 mm from the apex. Ventral and lateral surfaces converge to produce an elongate, gently tapering apical region. Guard converges anteriorly to produce a long, very attenuate stem and alveolar region. A long, relatively prominent Belemnopsis-like ventral groove extends to within 4–5 mm of the apex.

Discussion. Other Latady Group specimens are similar; it is possible that all Belemnopsis sp. C may be juveniles of other elongate Belemnopsis described. Other similar sized Belemnopsis and Hibolithes are also present at locality R.7519.

Range. Latest Bathonian – early Kimmeridgian.

Belemnopsis sp. D
(Figure 5.16)

Material. Two relatively poor latex casts (UTGD87356a, 87357c, Locality Q13). Both are fragments of apparently pre-adult specimens, including the alveolar region (crushed in 87356a), but the apex is missing. Part of the ventral surface, one flank, and part of the dorsal surface of each are visible.

Description. Guard slender, elongate, either parallel-sided or slightly hastate, c. 80 mm long, and 7–9 mm in maximum diameter. A narrow, relatively deep ventral groove extends for most of the length of both. Cross-sectional shape is uncertain, but appears to be either laterally compressed or equi-dimensional. No details of apical region are known, no lateral lines are visible.

Discussion. Both specimens are similar in some features to Belemnopsis mackayi (Toarcian, New Zealand). Both that taxon and these specimens are slender, elongate, and narrow grooved. However B. mackayi is poorly known, and comparisons are made more difficult by the pre-adult state of these specimens, their limited number and incomplete condition. The specimens are much younger than B. mackayi.

Range. Middle Callovian – early Kimmeridgian.

Belemnopsis sp. E
(Figure 5.17-5.19)

Material. Four latex casts (R.7507.5.1, R.7507.5.2, R.7507.9.9, R.7507.9.16), all anterior fragments.

Description. Outline slightly hastate and less so in profile. Largest specimen (R.7507.5.2), 35 mm long, 9 mm in transverse diameter posteriorly, 8.5 mm near anterior end. Flanks diverge slightly anteriorly from the point of minimum diameter, suggesting the alveolar region is present but alveolar cavity not preserved. Cross section slightly depressed throughout. Ventral groove moderately wide and deep, extends full length of the fragment, widening but not shallowing posteriorly.

Remarks. Specimen R.7507.5.1 is similar in size to R.7507.5.2; R.7507.9.9 and R.7507.9.16 are smaller, but all are similar in form.

Range. Early Callovian – late Kimmeridgian.

Belemnopsis sp. F
(Figure 5.20-5.22)

Material. Five latex casts (R.7504.3.24, R.7507.5.7b, R.7507.5.8, R.7512.2.3; UTGD87058c, (Q17).

Description. Guard is small, short, robust, typically < 30 mm long, 4–5 times maximum diameter. Outline symmetrical and hastate. Maximum diameter located near mid-guard, usually just posteriorly placed, apical region short and obtuse. Guard tapers anteriorly to produce moderate transverse hastation. Profile hastate, less so than outline, cross section strongly depressed. Ventral groove wide and shallow, and terminates close to apex. Lateral lines are not evident.

Discussion. The variation in profile suggests that features derived from more than one taxon may be included in this description. This possibility cannot be further studied with the available material. Specimen R.7507.5.7b (Figure 5.22) differs in profile from the other specimens; its ventral surface is almost flat, dorsal surface at first diverges rapidly from the apex without curving markedly, then diverges more gradually anteriorly, producing an unusual, wedge-shaped apical profile.

Range. Early Callovian – late Kimmeridgian

Belemnopsis sp. G
(Figure 5.23-5.25)

Material. 3 latex casts (R.7507.3.6a, b, c), all of apical fragments, 1 poorly preserved. The best preserved is R.7507.3.6a.

Description. Longest specimen c. 27 mm long, flanks and dorsal surface converge regularly to produce an elongate apical region with a sharply pointed, dorsally placed apex. Ventral surface more inflated than dorsal surface, converges towards apex earlier than dorsal. Ventral groove moderately wide and deep, terminates close to apex. Cross section at anterior strongly depressed, c. 9.3 mm wide and c. 7.5 mm high.

Discussion. It is possible that Belemnopsis sp. E and B. sp. G are fragmentary specimens of the same taxon. All were found at the same outcrop, although at different horizons. They are all of comparable diameter and have similar ventral grooves. However, the strongly depressed apical regions (sp. G), contrasts with the weakly depressed anterior fragments (sp. E). Guards of Belemnopsis are often depressed posteriorly and less depressed anteriorly, but if Belemnopsis sp. E and sp. G are conspecific, the difference in cross sectional shape is unusually large. They may conform, particularly B. sp. G, to the "European-type Belemnopsis" concept of Doyle et al. 1996.

Range. Latest Bathonian – early Callovian.

Belemnopsis sp. H
(Figure 5.26-5.27)

Material. Two latex casts (R.7507.9.4 b, c), both of apparently almost complete specimens.

Description. Guard is short and robust, length about three times maximum diameter. Observed length c. 20 mm, maximum diameter c. 7 mm. Outline slightly hastate, widest point near mid-guard, flanks converge slightly anteriorly. Profile non hastate, dorsal and ventral surfaces subparallel for most of guard length. Apical region short and blunt. Ventral groove strongly developed, relatively wide and deep, extending from alveolar break almost to apex. Cross sections compressed. Alveolus deep, estimated depth one third of guard length.

Discussion. The specimens are similar in gross proportions to Belemnopsis sp. F, but differ from that taxon in their compressed cross section and strong ventral groove.

Range. Late Kimmeridgian.

Belemnopsis (or Hibolithes) sp.
(Figure 5.5-5.6)

Material. One cast of the anterior parts of an adult specimen (R.7517.28).

Description. Moderately to strongly hastate in outline and profile; dorsal and ventral surfaces and flanks converge steadily towards anterior. Cross section strongly compressed throughout; posterior c. 12.5 x 16 mm; anterior c. 9.5 x 12.5 mm. Moderately narrow, shallow ventral groove extends full length of fragment, weaker at anterior end (the reverse is usually true of Belemnopsis and Hibolithes – the anterior weakening, and the shallow nature of the groove may be a preservation effect or an artifact of casting). No details of alveolus and apical regions are preserved.

Discussion. We are uncertain if this specimen should be placed in Belemnopsis or Hibolithes. It appears too large and too strongly grooved for Hibolithes, and too weakly grooved for Belemnopsis. It shares the generally compressed cross section of Belemnopsis mackayi Stevens and B. deborahae Challinor (Toarcian, New Zealand), although the guard is more hastate and the groove is shallower than is usual in both. B. compressa Avias (Bathonian – Callovian, New Caledonia) is similar in cross section and hastation, but the groove is much stronger. The wide, very shallow dorsal alveolar groove that occurs in some specimens of the three taxa compared is not present in our specimen. Given the nature of the groove in those taxa, it would not necessarily be visible in latex casts.

Range. Latest Bathonian – early Callovian.

Belemnopsis spp.

Material. A number of latex casts, all anterior fragments, possibly of several different taxa. The material is inadequate, and they are not described but listed here to complete the record. Specimen UTGD87357a, 87349a, locality Q13; UTGD87367a, 87366c, 87362a, Q9; UTGD87199, 87218a, 87261b, Q4.

Genus HIBOLITHES Montfort, 1808.
(Figure 6)

Type species.- Belemnites hastatus de Blainville, 1827. Upper Callovian – Tithonian.

Diagnosis. Guard moderately elongate, moderately robust, usually moderately to strongly hastate, sometimes strongly club-shaped. Widest/deepest part usually in posterior half, sometimes close to the apex. Cross sections depressed, equi-dimensional, or compressed. Median ventral groove narrow, shallow, occasionally more strongly developed; commences at the alveolar break, sometimes restricted to alveolar and anterior stem regions, sometimes extends to about mid-guard, occasionally into the apical region. Alveolus short compared with guard length. Double lateral lines usually well defined, particularly in the apical half of the guard, less so anteriorly. Juvenile and early immature guard slender, elongate, and strongly hastate (our concept).

Hibolithes catlinensis (Hector, 1878)
(Figure 6.1-6.5)
1965 Hibolithes catlinensis, Stevens, p.261, pl.14,
figures 1, 2, 6-8, 12, 16-18, text figure 26a, and synonymy therein.

Material. Latex casts of eight specimens. Descriptions based mostly on four specimens; UTGD87277a (Q10), (Figure 6.3), an almost complete near adult specimen; UTGD87277b (Q10), (Figure 6.4-6.5), a partly exfoliated adult stem fragment; R.7506.4.1 (Figure 6.1-6.2); anterior half of an adult guard; R.7505.2.106, a pre-adult fragment. Remaining four fragments: R.7505.2.42, 107, 109; R.7506.1.3.

Description. The most complete specimen (Figure 6.3) c.110 mm long and c. 12 mm in maximum (dorsoventral) diameter. Most of one flank and dorsal and ventral surfaces of the apical 50 mm of the specimen visible, anterior dorsal and ventral surfaces partly concealed, one flank is completely concealed. Outline symmetrical and strongly hastate. Widest point on guard is c. 20–25 mm from apex. Visible flank converges regularly towards guard midline producing a long very attenuate anterior stem and alveolar region. Profile slightly asymmetric; one surface (? dorsal), slightly inflated near the widest/deepest part of guard. Dorsal and ventral surfaces converge regularly anteriorly to produce strong sagittal hastation. Dorsal and ventral surfaces, and flanks converge regularly towards the partly concealed apex. Cross sections compressed. Dorsal and ventral surfaces and flanks regularly rounded in the apical third of the guard, dorsal and ventral surfaces more acutely rounded than flanks. No details of alveolus, ventral groove, or lateral lines preserved. Figure 6.4-6.5 is a hastate stem fragment c. 25 mm long and c. 9 mm in maximum (dorsoventral) diameter. It is partly exfoliated, laterally compressed throughout, and a narrow shallow groove extends along its ventral surface. Weak lateral lines are preserved on one flank. Shape and size suggests it is a fragment of the mid or anterior stem regions of an adult.

Figure 6.1-6.2 is the anterior stem region of a large guard, c. 50 mm long, and strongly hastate in outline and profile. Cross section compressed throughout (c. 11.7 mm wide, c. 12.6 mm deep posteriorly, c. 7.2 mm wide, and 8.5 mm deep anteriorly. Compression and hastation both accentuated by exfoliation of anterior surfaces; the remains of an early growth stage project from the exfoliated anterior. A short, partly exfoliated, moderately wide ventral groove extends down the fragment for 20–30 mm. What appears to be the protoconch is preserved at the anterior end.

Specimen R.7505.2.106 is a slender pre-adult guard 75 mm long; part of the apical and anterior regions missing. Part of dorsal and the dorsolateral surfaces of one flank visible, the ventral surface is concealed. No ventral groove visible but lateral lines are evident over much of the visible flank.

Discussion. UTGD87277a (Figure 6.3) is a guard less mature than specimens of Hibolithes catlinensis figured by Stevens (1965) as plate 14, figure 1-2, 6-8, and more mature than figure 16-18. New specimens currently being studied from southwest Auckland and southeast Otago, New Zealand, are similar in size and morphology. The only apparent difference (and this may be a result of the few specimens available, and of their preservation) is that the ventral groove in Figure 6.1 is shorter than in most adult H. catlinensis. Hibolithes catlinensis is a long ranging taxon in New Zealand (early Bajocian to late Bathonian, middle and late Temaikan) and is now known to also be present in the Temaikan of New Caledonia (new unpublished data).

Range. Latest early Bajocian.

Hibolithes cf. H. marwicki Stevens, 1965
(Figure 6.6-6.9)

cf. 1965 Hibolithes marwicki marwicki Stevens pl. 18, figures 1-9, 11-17; pl. 19, figures 1-9, 13-18.
cf. 1986 Hibolithes aff. marwicki marwicki Mutterlose figure 4a, b.
cf. 1999 Hibolithes marwicki Stevens, Challinor figures 45-70.

Material. Two latex slabs, (R.7508.13.9 and R.7508.13.ll (Figure 6.6), with fragments of at least 20 partial specimens, most broken and distorted, semi-aligned on bedding planes. One specimen is almost complete.

Description. Guard very elongate, slender, hastate in outline and profile, c. 100 mm long, and 7–8 mm in maximum diameter. Widest and deepest points on the guard are apparently located about one third the distance from apex to anterior. Guard tapers posteriorly to produce an elongate apical region, possibly with some ventral inflation. Apex centrally or slightly dorsally placed. Guard tapers anteriorly to produce an elongate slender stem and alveolar region. A narrow ventral groove, deeply incised into the surface of the guard, is present anteriorly and extends well down the guard (Figure 6.7-6.8). A natural cross section (Figure 6.9) suggests that it may extend into the apical region in some specimens. Cross sections laterally compressed, dorsal and lateral surfaces regularly rounded, ventral surface is maybe slightly flattened.

Discussion. The specimens resemble Hibolithes marwicki Stevens (middle Tithonian, New Zealand), in their very elongate, slender, hastate form, compressed cross section, and narrow ventral groove (cf. Stevens 1965, pl. 19, figures 1-9; Challinor 1999, figures 40-42, 45-46, 49-50). Mutterlose (1986, figure 4a, b), identified as Hibolithes aff. marwicki a calcareous specimen similar to this material (and similar to Challinor 1999, figures 45, 46), from his locality 8, also in the Bean Peaks, but some 5 km to the east. The material studied here is poorly preserved, consists of casts, and it is not claimed to be conspecific, although the resemblances to H. marwicki are strong.

Range. Late Oxfordian – late Kimmeridgian.

Hibolithes aff. arkelli Stevens, 1965
(Figure 6.20-6.21)

aff. 1965 Hibolithes arkelli, Stevens, pl. 15, 17, 17, figures 1-5, 7, 8; pl. 18, figure 10; text figures 24g, h; 25a-d (see synonymy therein)
?1986 Hibolithes aff. marwicki, Mutterlose, p. 8-10, figures 6a-b, g-j.
aff. 1999 Hibolithes arkelli Stevens, Challinor, p. 381-383, figures 71-93 (see synonymy therein)

Material. Two poor quality latex casts (UTGD87221a, d; Q2). One is almost complete, but much of one flank is missing; the other is an alveolar fragment.

Description. Guard elongate, outline hastate, moderately robust, largest specimen (Figure 6.20) 81 mm long, 6-7 times maximum diameter. Widest part posteriorly placed, c. one third the distance from apex to anterior. Stem tapers anteriorly, flanks converging to minimum separation, (presumably at about the position of the protoconch), then diverging anteriorly. They converge posteriorly from widest point producing a moderately elongate apical region with a moderately acute apex. Profile similar to outline but less hastate. Cross section approximately equi-dimensional posteriorly, compressed anteriorly. Median ventral groove moderately wide, shallow, apparently confined to alveolar region and anterior stem. Groove more strongly developed in the anterior fragment, may be poorly reproduced in the complete specimen. No information on alveolus preserved. No lateral lines evident.

Discussion. The specimens are generally similar in size, shape, and hastation to the more hastate specimens of Hibolithes arkelli (Middle Tithonian, New Zealand) (Challinor 1975, figures 23-24, 36-37), but if the interpretation of cross section above is correct, they are less laterally compressed, and the ventral groove does not extend as far down the guard. However, H. arkelli is variable in both these features (Challinor 1975, figures 11-13, 20, 37). Mutterlose (1986, figure 5a, b, g-j) described Hibolithes aff. arkelli from Bean Peaks (his localities 7, 8), and Wilkins Mountains (loc. 2, 4) Orville Coast, Ellsworth Land. Crame et al. (2000) described a fragment identified as Hibolithes aff. arkelli, recovered from a bottom trawl in the eastern Weddell Sea. Willey (1973) described Hibolithes belligerundi (Tithonian, West Antarctica), Hibolithes antarctica and Hibolithes sp.nov (Berriasian, West Antarctica) from Alexander Island. All resemble H. arkelli in some features. The specimens have some features in common with H. savornini (Kimmeridgian-Tithonian, Madagascar, Combémorel 1988). The presence of several similar taxa of Tithonian or Tithonian-Berriasian age in the West Antarctica region and the poor quality of the casts makes identification difficult.

Range. Middle – latest early Kimmeridgian.

Hibolithes sp. A
(Figure 6.13-6.14)

Material. Two latex casts (R.7519.60.30a, b) of early juvenile growth stages; each lying (apparently on one side) parallel to a bedding plane. R.759.60.30a is complete, R.751960.30b lacks the anterior half.

Description. Guard small, slender. R.751960.30a (Figure 6.13) 33 mm long, maximum (sagittal) diameter c. 2.2 mm; deepest point on guard c. 4 mm from apex. Dorsal, ventral, and lateral surfaces converge posteriorly producing a moderately obtuse apical region with a centrally placed apex. Guard contracts anteriorly producing an extremely attenuate stem region c.1.3 mm in diameter 16 mm from apex and 0.6 mm in diameter 30 mm from apex. Anterior 3 mm distorted into a flattened triangular shape (apparently due to crushing of alveolar region). Cross section in apical region apparently equi-dimensional, compressed anteriorly. No alveolar or other grooves present, no lateral lines seen. The incomplete specimen (Figure 6.14) c. 19 mm long, similar to the posterior half of Figure 6.13 (the long slender anterior region presumably detached before burial or lost during collection).

Discussion. The specimens are included in Hibolithes solely on their hastate clublike profile. They are two of several juvenile specimens, including Belemnopsis, from several horizons at outcrop R.7519.

Range. Latest Bathonian – early Callovian.

Hibolithes sp. B
(Figure 6.15)

Material. One latex cast (R.7507.9.19) that includes the stem and possibly part of the apical region.

Description. Guard slender, hastate, fragment c. 60 mm long. Flanks diverge slightly near the anterior suggesting part of the alveolar region is present. Posterior maximum transverse diameter c. 7.9 mm, sagittal diameter c. 8.2 mm. Minimum (anterior) transverse diameter c. 6.6 mm, sagittal diameter c. 8.2 mm. The cross section slightly compressed throughout. Ventral groove narrow, shallow, extending full length of fragment. It is very weak anteriorly, a region of the guard in which the ventral groove is usually more strongly incised (possibly a preservation effect).

Discussion. Almost all New Zealand Hibolithes have long ventral grooves (extending to mid-guard or into the apical region). Hibolithes sp. B has a long groove, but this feature cannot be evaluated further with the material available. Its cross section is less compressed, it is less hastate, and its ventral groove is not as narrow and well incised as that of Hibolithes cf. H. marwicki above.

Range. Late Kimmeridgian.

Hibolithes sp. C
(Figure 6.16-6.17)

Material. Two latex casts (R.7504.3.15, R.7504.3.87), of complete specimens exposed on bedding planes. In the better-preserved specimen (Figure. 6.17), one flank and most of the posterior dorsal and ventral surfaces are visible. The dorsal and ventral alveolar and anterior stem regions are partly concealed. The cast appears to be slightly crushed or distorted posteriorly. The other specimen (Figure 6.16) is flattened and distorted, and provides no information on cross section, but both ventral groove and lateral lines are preserved, although poorly.

Description. Guard elongate and moderately slender, maximum dorsoventral diameter c. 11 mm, length 90 mm, and c. 8 times maximum diameter. Profile hastate (anterior sagittal diameter c. 6 mm) and asymmetrical, posterior ventral part of guard inflated. Apical region moderately obtuse, apex dorsally placed. Outline hastate, probably more so than profile. Cross section compressed posteriorly, apparently less so anteriorly, although this may be due to distortion. Strong lateral lines and an alveolar groove c. 35 mm long are present on the flattened specimen. The alveolus is shallow and penetrates the guard for about one fifth of its length.

Discussion. The better-preserved specimen (Figure 6.17) resembles New Zealand Hibolithes mangaoraensis Stevens, 1965 (middle Tithonian, Challinor 1999, figure 11-38), in its ventral inflation and cross section, but both specimens are more elongate and the ventral groove is much shorter (Figure 6.16) than in H. mangaoraensis.

Range. Latest early – middle Oxfordian.

Family DICOELITIDAE Sachs and Nalnjaeva, 1967
Genus DICOELITES Boehm, 1906
(Figure 6)

Type species.- Belemnites dicoelus Rothpletz, 1892. Upper Jurassic.

Diagnosis. Guard moderately elongate and robust, to very elongate and slender, subcylindrical to hastate. Mid-guard cross section slightly to strongly depressed. Median ventral groove moderately narrow, deep, and well incised into guard surface may be wide and deep in robust forms. Extends well into the apical region, sometimes almost to the apex. Median dorsal groove short, shallow, often very weak, usually confined to or near the alveolar region, occasionally extending further down the guard. May be missing in some adults, more often in pre-adults. Alveolus short in relation to guard length, lateral lines moderately or poorly developed (our concept).

Dicoelites sp.
(Figure 6.10-6.12)

Material. Two latex casts (R.7519.17.11, R.7519.24.51), both alveolar/stem fragments.

Description. R.7519.24.51 (Figure 6.10-6.11), a slightly hastate fragment c. 20 mm long, midpoint 5.5 mm in transverse diameter, 6 mm in sagittal diameter. Cross section is compressed, prolate, with rounded flanks and dorsal and ventral surfaces. Vague circular markings at anterior end suggest the alveolus is present. A deep and narrow median groove extends long the ventral surface. A short, shallow, narrow, median dorsal groove extends about 10 mm along the dorsal surface, terminates c.10 mm from the anterior (termination prior to the end of the guard may be an individual feature of this particular specimen, or result from damage to the mould). R.7519.17.11 (Figure 6.12), an alveolar/stem fragment 45 mm long. Maximum and minimum lateral diameters are 6.3 and 4 mm; dorsoventral diameters are 5.5 and 4 mm; specimen hastate in outline and profile, cross section depressed. Lateral, dorsal and ventral surfaces regularly rounded. A deep and relatively narrow ventral groove extends the full length of the fragment. No groove visible on damaged dorsal surface of the alveolar region (but the alveolar end suggests a dorsal splitting surface remnant, the "slit" of Krymholz 1992, may be present). Faint lateral lines extend the length of the specimen, they are situated at the midline at its posterior end, and migrate slightly towards the ventral surface in their anterior course.

Discussion. Dicoelites occurs in New Zealand (Kimmeridgian and early/middle Callovian, Challinor 1980, and new data), Madagascar (Callovian-Oxfordian, Combémorel 1988), New Caledonia (Bathonian, Challinor and Grant-Mackie 1989), and in South America and West Antarctica (Middle Jurassic, Doyle et. al 1996), but does not seem to be abundant in any of these regions.

Range. Latest Bathonian – early Callovian.

Family DUVALIIDAE Pavlow, 1913
Genus DUVALIA Bayle, 1878
(Figure 6)

Type species.- Belemnites latus de Blainville, 1827. Berriasian-Valanginian.

Diagnosis. Rostrum of medium size, generally more or less strongly compressed. Apex short, summit often rounded, sometimes mucronate. Transverse section oval or subquadrangular. Dorsal alveolar groove more or less elongated. Lateral lines transversing the flanks. They are generally visible in young rostra and weaken or disappear in adults.

Duvalia aff. rhopaliformis Combémorel, 1988
(Figure 6.18-6.19)

aff. 1988 Duvalia rhopaliformis Combémorel, p.16, pl. 21, fig. 1.

Material. One partial latex cast (UTGD87347a, Locality Q13). The specimen lies on one flank partially embedded in matrix. The posterior half is sufficiently well exposed to provide details of the posterior cross section.

Description. Guard hastate, small, moderately slender and strongly compressed. Preserved part of specimen c. 50 mm long, length c. 4.5 times maximum diameter. Maximum transverse diameter situated c. 18 mm from the apex, outline symmetrical, and strongly hastate. Flanks converge anteriorly to produce a moderately elongate stem region, more rapidly posteriorly to produce a moderately obtuse apical region. Dorsal and ventral surfaces taper steadily towards the anterior; converge more rapidly posteriorly producing a slightly dorsally placed, mucronate apex. Profile slightly asymmetrical, ventral surface slightly inflated near the deepest point on the guard. Cross section oval, strongly laterally compressed in the apical half of the guard; transverse diameter near widest point on the guard c. 8 mm, dorsoventral diameter c.11 mm. Cross section apparently more compressed anteriorly. Lateral surfaces of apical region gently rounded, slightly ventrolaterally flattened, dorsal and ventral surfaces are more acutely rounded. Parallel lateral lines, slightly ventrally placed, faintly visible near the midline of the guard towards the anterior. Alveolus not preserved, no certain alveolar groove visible. Short dorsally placed, narrow, weak depression c. 4 mm is length visible at guard anterior.

Discussion. The specimen closely resembles Duvalia rhopaliformis Combémorel 1988 (late Bathonian, Madagascar,) although the cross section of the latter is apparently less compressed. The short alveolar depression may be a groove remnant or a casting artifact.

Range. Middle Callovian – early Kimmeridgian.

Duvalia sp.
(Figure 6.24-6.25)

Material. One distorted apical fragment (R.7507.9.13) c. 40 mm long.

Description. Outline symmetrical, profile slightly asymmetrical, ventral surface more inflated towards apex. Cross section an irregular oval with moderately rounded dorsal surface, a wider more flattened ventral surface, gently rounded, slightly flattened flanks. One flank is crushed. Guard compressed, maximum dorsoventral diameter c.18 mm, lateral diameter c. 13 mm. Apex mucronate and dorsally placed.

Discussion. The cross section, although distorted, resembles that of Duvalia emerici (Neocomian, France, Combémorel 1973) in apical view.

Range. Late Kimmeridgian.

Genus PACHYDUVALIA Riegraf, 1981
(Figure 6)

Type species.- Produvalia (Pachyduvalia) pinguis Riegraf, 1981. Lower Oxfordian.

Diagnosis. Rostrum medium to small sized, hastate or subcylindrical. Cross section variably depressed, subquadratic or subpentagonal. Apical end round with mucro or blunt and excentric, apex closer to dorsal side. Ventral side flat to various degrees. Ventrolateral ridges and longitudinal depressions anteriorly, lateral lines strongly developed. Dorsal alveolar groove short, alveolus up to one third total length of rostrum (interpreted from Barskov and Weiss 1994).

Pachyduvalia aff. pinguis (Riegraf, 1981)
(Figure 6.26)

aff.1981 Produvalia (Pachyduvalia) pinguis Riegraf, taf. 8, fig. 81, abb. 240 (see synonymy therein).

Material. One latex slab (R.7507.9.4), containing the specimen described here (R.7507.9.4a) and several fragmentary Belemnopsis. The guard is completely exposed along the dorsal surface and one flank, the ventral surface is almost completely exposed, and one flank is concealed.

Description. Guard short, robust, 35 mm long, maximum diameter c. 10 mm. Widest point c. midway along the guard. Outline parallel sided or slightly hastate. Profile asymmetric. Deepest point midway along the guard. Dorsal and ventral surfaces converge anteriorly towards the midline producing slight sagittal hastation, then diverge again. Dorsal and ventral surfaces and flanks converge posteriorly producing a moderately obtuse apical region. The exposed flank is eroded. Eroded lateral lines extend posteriorly along the midline from the alveolar break and appear to be deflected dorsally near the apex. Apex mucronate and dorsally placed. Cross section compressed. Dorsal and ventral surfaces rounded, visible lateral surface is flattened. Alveolus deep, penetrating c. half the guard length. No alveolar groove visible on preserved part of the guard, dorsal and ventral surfaces identified from the asymmetric profile.

Discussion. This specimen resembles Pachyduvalia pinguis Riegraf (early Kimmeridgian, Germany) in profile, outline, and, as far as can be seen, in cross section. The strong alveolar groove of P. pinguis is not present.

Range. Late Kimmeridgian.

Pachyduvalia aff. agricolae
(Parona and Bonarelli, 1897)
(Figure 6.27)

aff.1994 Produvalia (Pachyduvalia) agricolae, Barskov and Weiss, p. 93, fig. 6i, j (see synonymy therein).

Material. One latex cast (R.7507.9.8) exposed on the surface of a latex slab. Three sides of the specimen are partly or completely exposed, the remaining surface is obscured.

Description. Guard short, robust, maximum diameter c. 8 mm, length 40 mm. Widest point c. halfway along the guard. Exposed surfaces converge slightly anteriorly to produce transverse and sagittal hastation. They converge posteriorly towards the apex, at first gradually, and are then drawn out terminally into an extremely long, tapering, centrally placed mucro. Cross section of guard rounded, either compressed (if the completely exposed surface is a flank) or depressed (if the exposed surface is dorsal or ventral). No lateral lines or alveolar groove visible. If originally present the latter may have been restricted to an unpreserved part of the guard or may be present on the concealed surface.

Discussion. The guard is of unusual, bottle-like shape, and, given the apparent absence of a dorsal groove, is placed in Pachyduvalia mostly on gross form. If not so placed it is difficult to know in which taxon it should be included. It resembles Pachyduvalia agricolae (late Callovian-early Oxfordian, Crimea), a taxon with similar shape, mucro, and depressed cross section, illustrated by Barskov and Weiss (1994, figure 5i, j). Our specimen strongly resembles P. agricolae, but is slightly more slender and elongate.

Range. Late Kimmeridgian.

Genus RHOPALOTEUTHIS Lissajous, 1915
Type species.- Belemnites sauvanausus d`Orbigny, 1842
(Figure 6)

Diagnosis. Rostrum of moderate size, in the form of a club, but sometimes perfectly straight. Transverse section circular, oval, or subquadrangular, but never compressed. Apex more or less elongated, rounded, or mucronate. Dorsal alveolar groove narrow and deep. More or less elongate. Apical line slightly excentric.

Rhopaloteuthis sp.
(Figure 6.22-6.23)

Material. One latex cast (R.7507.1.2). Most of the (presumed), dorsal surface and much of the lateral surface are exposed, the ventral surface is concealed.

Description. Outline hastate, widest point situated c. 15 mm from apex. Flanks converge regularly posteriorly to produce a moderately obtuse apex, an apical pit suggests a mucro was originally present. Transverse diameter at the widest point c. 8 mm (ventral surface of the cast concealed, dorsoventral diameter cannot be measured). Apical view suggests the specimen is approximately equi-dimensional, apical cross section subpentagonal. Alveolar region crushed; a shallow, narrow, presumably dorsal groove extends for c. 10 mm down the guard. Alveolar depth uncertain, but alveolus apparently extends into the guard for up to half its length.

Discussion. This specimen resembles Duvalia monsalvensis (Callovian-Oxfordian, Madagascar) and Duvalia zaferai (Oxfordian, Madagascar, see Combémorel 1988, pl. 21, figure 4, 19), although the dorsal groove in both of these is more extensive and the cross section compressed. Our specimen is robust, its apical cross section is c. equi-dimensional, and it seems better placed in Rhopaloteuthis. We have placed Pachyduvalia aff. pinguis and P. aff. agricolae in that genus because of their specific resemblances. Rhopaloteuthis sp. is placed in that genus because it conforms better to the generic description and is present in Madagascar at about the same time (Combémorel 1988).

Range. Latest Bathonian.